Fed Up

I am frustrated this point and just exhausted at this point. My children’s father has been working towards “getting his family back”, I am not interested in being with him and especially not now. I’m realizing there were several reasons we broke up & one of them being us constantly at each others neck because he allows his mother to cross boundaries time after time again. I will discuss my issue regarding something his mom does with our children then, we come to a solution and then boom it happens again and it has me wondering did he ever even speak to her or set boundaries with her? Doubt it. I do not allow my mother to cross boundaries and I stand firm on them, stuff that WE agreed on as parents will be enforced on my end always. It doesn’t help that she makes super weird comments about me working and always insinuating that I need to be at home taking care of my children. I tried being a SAHM & it’s bad for my mental health being home all the time plus I’m literally the ONLY one financially providing for both of my children so why wouldn’t I work? Idk I don’t think I can even attempt to be with somebody like this. How would you react in a situation like this? Am I overreacting?