Step daughter advice needed

So I have got to a point that step daughter and I don't speak or have contact any longer, I have always tried made lots of effort and my partner agrees it a problem on her side as she doesn't want to play "" happy families "" her words not mine she is 25 and mainly lives her own life with her partner job and leaves us alone to do our own thing, her partner has started to work away and I said to partner she will want to spend time with u more as a result I'm usually absolutely fine with it, they are going to a concert together and a event later next month not a issue at all, I work part time and we usually spend days off Mon /Tues together, I have to work Tues and she is wanting to spend Monday with him but without me am I been unreasonable to not be well pleased about this at times, I think it's rude that when she knows I'm day off also to always just invite him and not me to do anything, partner has had words but it didn't achieve anything, I tried to talk via text and it just got ignored so to save face I just gave up after ll I cannot force her to like me, I'd like to add I have not done anything to this child and when asked by her father agagin she said I haven't done anything she just apparently finds me weird and doesn't want to play happy families, I love my partner very much and he's so good with my child and family I couldn't wish for a nicer man, I don't want to lose him but I don't know if I can be put second which I absolutely expect to be to his child but I feel like she's getting away with it!

I don't want to. Lose him or let it affect us but I am afraid it is affecting me deeply I have borderline personality disorder so find it hard to regulate my emotions but I'm heartbroken by her behavior towards me

Do I stay with this man or do I try and plan a future away from him for his daughter sake I need advice