Witch MIL ...to breakup or not

So my MIL hates me. A little background to that is her son whom I have been in a serious relationship with for 4+ years, has anger issues. He broke my card door and smashed a window at one point and I called the cops. MIL insists the issue is me and hates me for bringing in “so much drama” to his life 🙄 ...but whatever me and him worked through ALOT and did couples therapy so we got passed it. She still hasn’t. She makes shitty ass petty remarks to him like, if I need to come over I have to clean her sons room AND her bathrooms even though I haven’t been there in months and only went ONCE because my baby was sick. I stopped letting my kids stay with her because she favored one over the other until she flat out said only my son could stay not our daughter. Then yesterday he posted a picture of me and him together at a wedding and she immediately commented something to the effect of “I told you to please post pictures of the little kids not the big ones” ...you guys I think I’m reaching my breaking point. It’s borderline disrespectful. But what irks me the most is that he refuses to defend me and stand up to her. He allows her to badmouth me and disrespect me when I never have. Today is Easter and because we argued about this he chose to go to his family instead of being with me and his kids. I think I may just break up with him. Is it wrong for me to let him go because I feel like he’s choosing his family over me? Am I being unreasonable? I’m so conflicted by this that I just lose respect for him as well.