Honestly.. while I get that she may be bending the story to fit her narrative.. it really serves no purpose to play "gotcha" with her.. all it does is make you look petty and mean.. and while I get that it annoys you that your DH gets mopey and you get mad at her for not making more effort to come over.. I recall my own life as a teen that age. and for what it's worth.. I didn't have a whole lot of interest in spending time with family.  maybe my own room.. but  hanging out with mom/dad? little brother? nope.. I was with friends.. doing teen stuff.. pulling away from the family. it's totally normal.

Honestly I agree you should disengage.  But it's also healthy for her to, once in a while, have someone let her know they're not buying it.  So when she said, I'll be here every weekend, I actually think it's healthy for her to have someone call her on it.  "Like you have so far?".  "well....I had stuff....".  So that the first time she decides to say that she's not coming, your DH can tell her "I thought you said you were going to come every weekend, I'm happy to drive you everywhere".  She either has to be honest with herself, or create a new narrative.  (She'll probably jump right to nobody over there likes me, so be very careful about the follow through on this).  If you can actually point out where she is hurting other people, maybe her eyes will open just a smidge and she'll follow through.  Not something you'd enjoy, but your DH might appreciate it!

I disagree. It may come across as petty, but its not. It's honesty. In YOUR HOME, you set the rules. Honesty is important. Accountability is important. Why should you have to play along with her lies in your own home? I think that is ludicrous. 

If you want to disengage to save yourself the headache of engaging with her, that's your choice, too. But don't for one second think you have to be a doormat to this bratty kid at your own dinner table. She needs to learn to respect you and her father when she is in your home. She can spread her lies outside your home all she wants, but that kind of toxic BS does not need to be the norm when she is with you. Hang in there. I know its exhausting. One of 3 of my toxic SD's are out of the house now, and its such a relief. 

I'm on the side of honesty for this particular SD is ok and at times needed.   With everything she has put you through, I can't believe you stuck around for dinner.  I would have left her to her dad and found better things to do.   I hope to that your DD did not change any plans do to SD showing up.  If anyone should be putting SD on notice , it should be DD.  
 

I had to deal with drama between my BD and OSD.  They are 1 year apart and in high school there was boyfriend drama.  Needless to say it did not end well and SD has burned that bridge with my bios. Can't expect to keep relationships when you act the whore like your mother.    

I agree you should let it go. I also hate liars and it feels so good to call them on their lies but it's not going to change what she does at this point. All it's going to do is make you seem like the bad guy to everyone. Your relationship with SD is never going to get any better but if you continue to act like this and call her out it's only going to negatively affect your relationship with everybody else. It puts them in an awkward position to see that you and SD are always at the edge of fighting. In that kind of situation people will pick sides and they aren't always going to pick yours.

Sometimes you can say more with a knowing glance and a smile than calling out directly. I do this with my SD and I know she gets the hint that I know she's full of it, but I don't look so evil doing it. 

This SD isn't going to get better.  She is making you angry.  Either ban her from your house, or leave when she comes over.

It seems like you have some unresolved anger towards SD, rightfully so, which means you haven't forgiven her. I honestly cannot blame you for any anger or resentment you are feeling, but somehow you have to find a healthy way to release it. If you don't, it will be like drinking poison and then expecting SD to die. 
 

If I were you, I would share some of that anger with your DH. Why does he think it is okay for SD to do all the things you mentioned and then come back into your home without an apology or acknowledge of her behavior? Not holding her accountable will allow her to believe she can say and do whatever she wants, which is what you are feeling.

Try figuring out ways to set boundaries, so that you can feel comfortable in your home. But in my humble opinion, your DH needs to help you create a healthier environment for you and your DD.

While I get why you said things to her, I think this situation should be a great wake-up call that you are in an unhealthy dynamic that needs a permanent change.

Your anxiety was so high that it made you forgetful? It caused you to lose your filter (and in a way that was honest but not productive - not that anything you said might be productive because it's your SD)? It caused you to put it all back on SD without looking at your DH as a BIG source of this problem by him not addressing both SD and his own issues with her?

I get why you said what you said, but please don't let this instance be something that makes you feel good long-term. It's a glowing red flag that there are some major changes that need to take place in your household. First and foremost - therapy for you if you don't already have it.

Additionally, SD needs to either come over when she is supposed to or stop coming. DH can see her outside the home if all she is coming for is dinner. I think very bluntly telling your DH that you're done with her BS and his moping is warranted. If all she is going to do is sit and lie at dinner, then you want no part of it. You're out - totally. You don't want to see her, you won't cook for her, you won't talk to her - you're out. If DH needs to talk about her, he needs to call BM, MIL, a friend, or a therapist because you're done.

Yes, you were being sarcastic and petty because you were fed up. No, it doesn't make you a bad person for doing it once. Yes, you need to make changes. There is a way of delivering honesty without sarcasm and pettiness, but if you're not a place where you can do that, then step out of all of it. Your DH won't be happy, but this is a mess her squarely made by not holding SD accountable sooner.

Though facts do matter.

So, keep putting the mirror in front of her face and make her live the consequences of her lies.  Particularly when she is using them for self aggrandizement in front of others. She can practice her self delusion in private.

She either learns and becomes a better person, or she continues to delude herself and continues to go through life without friends or anyone who respects her.

IMHO of course.

I get exactly where you are coming from with the frustration towards SD. I also agree that you need to find a way to channel the frustration away from SD so the one liner comments don't sneak out. It will only cause unnecessary drama and stress. I had to take medication and therapy to stop mine and be calm enough to let what SD8 does go now. I hope it gets easier for you, sounds like your DH moodiness about SD wouldn't help. 

It sounds like your SD exhibits some of the characteristics of Narcissism - which can be easier to deal with once you have a deeper understanding.  There's no way to know from one post - but it is a worthless waste of your thought and energy to try to correct or verbally disagree with someone who conflates the truth and lies perpetually.  They have grandiose ideas of themselves, don't care about you, won't listen to logic and will only talk shit faster than you can respond to their last lie.

I might be completely wrong about your SD -  but I have one - and I have saved every email and text she sends me/DH for proof if I ever need it... Good luck and save your sanity and health!!