I was in a pretty much similar situation to you, in that when I met my DH, my own two (well brought up, I might add)  kids were in their late teens - his were aged 5 and 7 and their status as entitled snowflakes with too much power, just grew over the years.  Finally it all came to a head in about 2013 after a decade of this and I was thinking seriously of leaving him.  He had a bit of an epiphany, and finally realised that allowing his kids, who were by then in their mid teens, to ride roughshod over him was doing no-one any favours. 

I really think that as your step kids are in your house ALL the time, you should have equal authority with your partner to discipline them.  And if you don't, maybe this relationship isn't a good fit for you, long term.  

I think it's normal to be annoyed by poorly behaved children that have all the power in a situation - but it shouldn't it be your DH your dislike is focused on? He's the one allowing them to behave this way.  Not disciplining children is lazy, neglectful parenting.

I can totally relate where you are coming from! Unfortunately you cannot change those kids. No matter what you do. Or your partner. The only thing you can do is find a way to live in the situation. The more personal you take things and the more you try to change things, the more resentment and anger you will have. It's been 3 years. Your partner is not going to change. And if I had to guess, the things that the kids do will get worse. The values that you raised your children with are not appreciated or wanted. It's hard. It was the hardest thing I EVER went through. It's the little things. Them living under YOUR roof and not giving you the same respect that most strangers would give you. My DH ex wife has nothing to do with their 3 kids either. They are with us 24/7 minus a day or 2 a  month if she decides she has time for them. Some stepkids like/respect their step parents. Some do not for what ever reason. No matter what you do. If you continue to see no change, let it go. Step back. Those are not your monkeys. Not your circus.  

Then you are with in your right to make rules and give out punishment for breaking the rules.  You can not live in a home with SK 24/7 and have no power over them.  You are the other parent ? You do the parenting things, you will get there respect.  It your DH doesn’t like it he can find a different place for his kids 

Keep reading these boards and it will stick out to you lke a sore thumb, and forefinger. Kids are kids and will try to test and push boundaries and buttons, thats what they do. I feel, from reading this post that your anger and frustration and dislike is being displaced - you are focusing all that on the kiddos. And they are just kiddos whos mother wants nothing to do with them and Ill bet the divorce/separation was ugly and painful to boot.

Here is what you presented:

Your partner doesnt parent.
Your partner doesnt back you up when you are attempting to parent.
Your partner puts the kids words and believes them OVER YOU.
Your partner subterfuges your efforts to teach manners and respect. Because he is not respecting you, he is teaching the kiddos not to respect you.

So. Clearly a partner problem. If you try to talk to him about these things, is he willing to listen. If you were to tell him, its just not a sustainable situation, I will have to leave if things do not change, would he try to stop you?

Not all children are likeable.   Even the best parent can’t change the inherent personality of their child. They can regulate behaviors but not who the child is at heart.  

RUN!!!!!!!!!!!!!!!!!!

Hello 

I am new and found this while searching for help. Super long storey me and my husband now married 3 years together 6 have 4 kids together from previous marriages I have 2 grown one living at home but grown and he has two daughters that are with us every other weekend and holidays etc. I tried my best accepting them as my own and my family opened arms to them and it was ok but my husband's ex has slowly and viciously since they were little worked them against me. This was enabled by my husband who gives in to anything she wanted and never set boundaries to respect our relationship. She would tell the kids I hate their mom and am a bad person and guiting them from having a relationship they are not even allowed to go home happy about anything like when I taught them to ride bikes or anything special we did. Well it's working they come over with attitude and I mean rude ! Spitting in my car, drawing on things they shouldn't and they know better they are 9 and 10. They do not appreciate a thing never a thank you and are rude to anyone who does anything for them to the point I asked my family to stop doing anything for them. My husband does nothing at all and I am giving up. I heard similar comments like hiding out or taking off and cringing expecially when husband wants to keep them longer and I feel horrible. I loved them and was such a good step mom but I can't take it any more and it's getting worse. I have talked to my husband he does nothing at all and doesn't like to deal with it or talk about it. I feel alone. Mother's Day nothing from them bday no happy bday and literally everything I do is wrong and not how their mom does it which I am fine with she's nuts and I am glad to be nothing like her 

I feel like jumping ship I never wanted this horrible blended situation any advice ? I was thinking step mom I would only wish for my kids to have and don't deserve it no one does it's a thankless job I get it but really do we have to put up with being treated like trash by everyone ? My kids however are very respectful and treat my husband like their own dad. This was important to me and I made sure he was treated well and I guess that's the difference right there