This is not a healthy relationship for anyone.

Honestly, you all need therapy (I'm not a huge therapy person, but y'all need it).

While you are all seeking help, you should not live together. 

This isnt healthy for anyone involved.  You two need to separate. Normal relationships do not involve physical violence from anyone or verbal abuse. Get counseling if you want to stay together, but you two need time apart for a while.

I agree with the other posters.
What can you expect from an 11 yo that is witness you and your BF hitting each other, both of you taught her that behavior right then and there. 

Also if I was 11 years old and I saw anyone hit my parent I would of hit them back, so I don't blame the girl. 
Then you invite them back? None of you should be in the same space until everyone works out their angry issues in some intense counselling. 
Maybe you should start with a sincere apology for your part in this whole mess, you still might not get an apology back however that is not the goal with a sincere apology. 
 

i couldnt get a word in i ended up hitting him.

Hitting me back with much force.

+++++++++++++++++++++++++++++++++++++

Huh?  You were mad because he hit you back harder than you hit him?  And you were going to hit an 11 year old?  Yes she hit you first but she just witnessed you attacking her father.  

All of this and you asked him to come back home??????  Why?  You are oil and water.  This is an extremely abusive situation,  And I am afraid to say that you are the abusive one.  

Get out of this and get some therapy.  

Don't you dare blame the pandemic and quarantine on this. You crossed a line by hitting your spouse, and then turning on a preteen who likely was reacting to her father being hit.

One of you need to move out, and it doesn't matter which one. Find a job tomorrow, doesn't matter what it is. But none of you are safe, and I'm not sure which is you is more dangerous.

When you swing first, you don't get to control how the other person retaliates to protect themselves or their child. Don't you dare try to blame him because he hit harder. 

Let this be a lesson to others: if you're at the point where you're about to cause bodily harm, leave. Don't care where you go, but go.

relationship but I have to say that you need to own up here. YOU hit your boyfriend. His daughter hit you in defense of her father (I would have done the same if anyone tried to hit either one of my parents) and then when you tried to hit her, he in turn defended his child from you. You are the abuser here. 

In truth he needs to apply for a restraining order to protect himself and the kids involved. Your first instinct is to use physical force. That does not say much for the future of the infant involved. 

I understand the frustration of having an unsupportive spouse.  Rather than helping with his daughter when you're putting the baby to bed he starts a fight with you.  You're tired, demands are coming from all directions and he's got the nerve to make things worse because you had the audacity to ask SD to go to her father for help.  

You hit him, he hits you. sd hits you, you go to hit her, Dh punches you in the head several times...WOW.  

As awful as the situation is and the fact that you were hurt the worst, if the cops would have been called DH could have rightfully claimed self defense and defense of his child. You hit him first so from a legal standpoint you were the aggressor and at fault.  That being said it was wrong of you to hit DH, and I personally believe it was wrong of DH to hit you back. He could have taken SD out of the space and walked away.  I can't imagine this is a first or out of the blue situation for the two of you.  If SD hit you she's either been hit or seen her parents/stepparents hitting each other before.  You're ALL abusive and imprinting this dysfunction onto your newborn.  

If they have a place to stay let them stay there. Bringing them home will do no good, nothing is resolved. You're not talking to them so what do you expect to happen when they walk in the door? DH will be protective of SD and SD of DH. It's them against you.  The slightest frustration and this will all start over again. God forbid you are holding your newborn when the hitting begins.  

I know it's hard to just go out and get therapy right now but there are probably counselors doing virtual and phone visits.  I would highly suggest reaching out for help. You need it! Your little baby needs adults who are good examples and a momma who knows how to resolve problems constructively.  

Please research the Cycle of Violence to see what happened and how it repeats over and over.  

https://dvbleedingheart.com/understanding-the-cycle-of-violence/

Try learning some nonviolent communication techniques:

http://imagoworks.com/couples-counseling/making-communication-work/

Not saying that you are the only one who should but once you change your approach they will have no choice but to change theirs.  

Above all, be safe. If you feel that you or your child are in danger please call 911 and get out at least temporarily.  

It appears you two have issues that were probably there before the lockdown.  I think for everybody involved it would be best to separate until you can both figure out how to interact with out devolving to hitting one another.  The fact that neither of you called the police leads me to believe this isn't your first round with physical violence.  Look into local programs that can help both of you, breaking this cycle will benefit the children not to grow up and accept this lifestyle as normal. 

Ok, obviously you are all ignoring OP JUST HAD A BABY. those of us who actually remember what it's like to have a newborn, and yes, this is a difficult time, so yes, it's valid to "blame". Hormones are all over the place, you're stuck at home with a new baby and a spouse that seems to suck too, and an SD that is annoying the shit out of you while you're caring for your newborn baby. Ummm, I at least understand OP. Y'all should give compassion and empathy a try before y'all try to insult and bash her. 

Yes it's f'ed up on so many levels. First of all, op mentions she couldn't even speak thanks to DHs arguing, that is frustrating asf and I wouldn't blame her smacking him to stfu so she could talk. SDs hitting her was COMPLETELY uncalled for, why is she getting involved in an adult situation??? DH hitting OP, mother of his child? WTF??? And y'all think OP is the one who needs help?? Seriously... 

I know how hard it can be, frustration and exhaustion is hard work. and when that bottles it often leaves us lashing out to get a point across.

You cant be mad at the child for hitting you, they will always protect their parents. this is to be expected- maybe a sit down conversation with child and dad about how adults are allowed to argue and fight and you wont tolerate them getting involved. make it educational and teach the child that violence on their part is not allowed, regardless of the situation.

As far as hitting your SO, yes i get it, but no its not ok. you can be mad but you cant be aggressive and all of the actions that evening are a direct responce to you becoming aggressive.

Read above youve apologised and thats awesome. maybe just have some clear rules in place and boundaries around new baby. prevention is the key, have healthy boundaries about tasks and when a parent is taking the responsibility for baby, other partner keeps the child occupied.

If you know your predisposed to aggressive outbursts when frustrated, make the decision to walk away instead of retaliate.

Hitting is never, ever OK.  From what I understand, you were the one to hit first - there is no excuse for this nor is there any excuse for them to retaliate in kind.  IMO you all need counselling. 

You should not be in this relationship. 

This was a very minor thing to get worked up about.  I still have to point out to my older children that I’m putting the younger children to bed. I doesn’t annoy me in the least, I simply say ‘I will come and see you in 20 minutes”. This is going to go on for years and years. It’s not the other kids fault. It’s just called a busy life. 

Do you need to get your hormone level checked after having a baby? 

Yikes! This is a powder keg waiting to blow. You should not have hit him, but the fact that he, the physically stronger one, took that as permission to punch and hit you with force, several times, is really scary. Most men would not react that way. 
 

You can get therapy now, it will be done by  video. Call around, but do it just for yourself as a starting point. 

ETA: Domestic violence in front of children is CPS reportable in NY, and the therapist will likely call, as he/she will be a mandated reporter.  Especially given that SD was actually in the middle of the violence.  There has been a big increase in domestic violence since the quarantine - people will be there to help you.

OP, what's your plan going forward?

You're in an unhealthy situation and stuck with no source of income, with a newborn. It's no wonder you're stressed. But you MUST change this, or you will surely repeat it and you will end up with more than a black eye.

Women's shelter? Counseling? Job options? What positive steps do you think you can take to help yourself out of this situation?

I truly hope you read the comments here and have stopped trying to reconcile with this man. He has hit you once- leaving a black eye- trust and believe he will do it again and next time you won't have to hit him first.

You were dead wrong in laying a hand on him. Yes, he was morally "more" wrong because I am sure that you did no damage in your hit but he did a number on you. None of this even matters anymore. You have to hope he doesn't press charges and you have no grounds to either. All you can do is move on. 

Find a friend or family member you can stay with. Look for a job. Set up a custody plan with him that leaves little or no contact with him. Parallel parent. Move one from this relationship. Before you enter into a new one, get counseling. Many counselors are doing sessions through Zoom. Both of my son's are. It works fine and you can start working through all of this but you do need help sorting through it all. 

When a relationship reaches a point that the couple is beating the crap out of each other, it has come to an end.

When a relationship reaches a point that the couple is beating the crap out of each other, it has come to an end.

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

 I had so many thoughts on this post since I disagreed with a lot of the responses.  But it all actuality...the above sentence is all that needs to be said.  

This sounds to me like the OP flipped out and attacked her SO and his DD.  Sounds like she was trying to violently push her SO out and the DD got involved.  Then she went after his DD.  THIS IS AFTER SHE HIT HIM AND HE HIT HER HARDER.  She was still being physical with him.  HUH?  Im sorry but this does not all add up.  

Im still surprised that everyone is A ok with the OP attacking him and his kid.  Was he not supposed to defend himself or his kid?  I guarantee if someone was attacking me, I would give them a beat down to make the attack stop.  BTDT and it saved my life.  Maybe this is how her SO thought.  And he probably held back on her or she would be MUCH more hurt than a black eye.  How long and how many hits should he have taken and not responded in kind?  Should he just let her keep coming at them?  

Based on some responses...I should have gone to jail because my attacker came out on the losing end of the attack...?

This is just mind boggling, If this were a man there would be no forgiveness.  It's not about who hit hardest. They are both mutually abusive, the kids are the victims here.  All of them.  She gets no pass from me, nor does he. BOTH are mutually at fault for this.  NOBODY is relishing she got hit harder, nobody is defending his actions.  They are both mutually at fault IMO.  She swung at him, she swung at a kid, he hit back, kid hit back.  Quit defending her and making him the villian.  Quit defending him and making her the villian.  BOTH are JUST as guilty and at fault IMO.  

And YES, I say this as someone who lived a very abusive relationship w/my exh, he was an abusive narc.

This blog tells me this is their norm, there ARE such things as mutually abusive relationships btw. 

It's appalling how people state that violence is no big deal if it doesn't leave a mark. There are plenty of violent actions that don't leave a mark. This household is violent regardless who leaves marks. Violent households shouldn't have young children residing there 

My advice immediately end the relationship.

Proceed to domestic abuse shelter and ask state for help.

Neither should have children living at home. SD needs to go to her grandparents. Little baby needs to go to any relatives for the time being 

Eventually maybe parents could have access to visiting their children but they should not have any custody wuth any children for at least some time. This situation needs to be put under control first. Children shouldn't be witnessing these fights