Co-Parentung as a SM

[TiredStepMum89]

A little back story.... I've been with my fiancé 4 years now and getting married next year.
BM has tried her hardest to make our lives hell the last 4 years (I was not the OW) but that's another thread 🙂 In the past she has made it very difficult for me to form a bond with SD by telling me I'm not allowed around SD sometimes, or that I should go away for the weekend when my DP has SD, she has told me I am not to do anything for her DD and has poisoned my SD against me (I know this because SD (5) tell me all the things "mummy" says about me) I have had years of abuse from this woman.

Here's my problem, the last few months BM had had a complete switch around and is now causing issues because I won't "co-parent". I am not her parent. When getting into my relationship I was willing to step up but after all I have been through, I no longer want to make the effort. When SD stays with us (every other weekend because BM moved 3 hours away) I am kind to her and I interact and do crafts with her, but I am fed up of being expected to spend "family time" with her and my DP. I'll be honest, I don't love SD, I like her, I don't love her.
She has a horrible attitude, is not disciplined and she has never been taught to tidy things away so it is left for me. I have stopped tidying up after her, I don't tell her off when she's rude, I don't correct her attitude, i dont even cook when she is here because the food is wasted.
I spent years being told I am not allowed to do those things but now BM and DP seem to expect that of me.
My partner is part of the problem, because he left her mum, he feels guilty for leaving his DD, therefore his DD gets her own way all the time.
I told him I was going away for his next weekend with SD because it my birthday and I haven't seen my friend for a year. I could see the disappointment in his face that I won't be here to spend time with him and SD. It gets on my nerves because I don't want to be and I shouldn't feel guilted into spending time with them. At this point, she's not my child so I don't understand why this is all expected of me suddenly after 4 years.
My question is.... AITA for not giving a damn? She can be in our house all she likes and I won't ignore her or treat her horrible, but why should I be so involved when I haven't been allowed for the last 4 years? I don't want to be anymore, and I've come to a point where I can happily live a separate life to her and her dad.
I'm have no doubt I'll get some hate for this but I feel what I feel 🤷🏼‍♀️

I think to be honest the ex being a nut or (not a nut) is really rather a red herring.

It's the other women scenario in reverse. In each situation the women are hating the other women and making excuses for their DH and focus on the OW. A women who sleeps with a married man could be described as someone with questionable morals. A ex wife who acts like a nut could also be described as someone with questionable morals.

But (lord above no one get to pissy about this next statement) your DH/partner is the person who is responsible for what effects your relationship. It takes two to tango but it also takes two to enable.

It's crap but not all men who have ex's allow this to happen. He maybe unlucky with his ex (who knows) but since he is the link between you both, then it's up to him to control the poison or the effects of the poison on the people he cares about since he has created this link.

If you say his ex is toxic I believe you. I have been around long enough on this board to see people justify what they want as a mum under the guise of "what's best for the children" but really it's about control.

And the end of a relationship should mean the end of the control. And although I believe these women are toxic, the men that enable them are equally bad if not more so,

Because they are in a relationship with you, not the ex wife or the ow. Should they do what they do in a moral level no. But they don't owe you anything but your partner does

Op - this isn’t going to get better.

The poor little girl is showing serious behaviour problems due to seriously terrible parenting by her mum and your partner. It will not get better. If she is behaving like this at 5 then she will be really problematic at 13. And when she is 13 you will probably have a 4 year old and a two year old who she will hate and will be really vulnerable to her hurting them.

4 years of being treated shittily and then they turn around and put the onus on you AGAIN! No wonder you're fed up and want to disengage. There's nothing to stop them turning against you again. Your partner needs to understand this and your boundaries and support a measured re engagement at your own pace and conditions. If that is limited with conditions that is what is needed. You are perfectly right to protect yourself here.

Long term SD is young so you need to consider what your long term goals are IE friendly aunt like figure etc or partner of the father both of which need RESPECT from all sides.

These people need to realised that you went into this with the best intentions to be involved OP. You've been treated poorly for 4 years by both dp and dsds mum. So how are they surprised now you've said you're stepping back and not being involved?!

You do you. Step back and do things how you want to. You have no parental or financial responsibility to that child, so it's your choice how involved you want to be. They're just going to have to deal with it.

Seriously?