AITA for how I handled this situation?

My boyfriend (26) coparents with his ex wife (27) and today told me she’s back to self harming again. I told him if he’s worried about harm coming to their shared child, he should push the divorce they have been dealing with and try to get main custody. We have already seen signs of neglect and abuse, I w tried opening dcfs cases for him to brush them off, and with no custody agreement set in stone, I’ve recommended him just keep their child but he won’t. He then told me to let his ex wife hurt their child, because then he would have actual evidence to use against her, and as a mom, that didn’t sit right with me. I brought it to his attention that the comment had bothered me, and made it feel like he was hoping she would hurt their child so he could take her, and asked if he had meant for it to come across that way, and now he said I’m an awful person who as a single mom doesn’t have to deal with shared custody, and that I need to educate myself on how fathers are looked down upon. I’ll quote the exact text below, but now he won’t talk to me. We’ve been together over a year now, have plans to move in together, etc, but I don’t know what to do. Anytime I have a concern, or an issue with something he says or does, and I try to raise attention to it, I basically get told to hit the road if I can’t handle it. I’m conflicted. I love them both. I want this so badly to work. But I can’t be on eggshells constantly and bottling everything up. I don’t want resentment. I don’t want to feel pushed down and not cared for, but I also know he’s gone through a lot of abuse and trauma with his ex. I’m talking physical, emotional, mental, the works. He is in therapy. He is on meds. He also works full time blue collar anywhere from 10-15 hour shifts weekdays. But I want to know what I can do. If anyone else has been in a similar situation where their partner gets scared you’re going to leave and tries to pull the trigger before you do because in the past they have dealt with issues whenever they try to talk something out. Help. I’m desperate to make this work. I love him more than I can ever explain. And I want his daughter to grow up happy. Texts are down below. H is my boyfriend, M is me. This is exactly how the conversation went. After he told me she was SHing where he could see on her leg and I raised concerns that she might harm their child. (She’s already been neglectful)

H: Let her cut B. I cant go to the court and say shes a threat because she might do something I need proof and actual actions are good evidence

M: This worries me ^

H: Why?

M: I’ve been sick to my stomach since reading it

H: Sick of me?

M: No. Just reading it made my stomach turn and I can’t shake the feeling

H: I mean yeah id rather B not get hurt but the only way anything is going to happen is if shes being hurt because A lies and makes shit up as you already know and irrefutable evidence is the only way I win

M: I just can’t imagine saying that about my daughter. I know you need concrete evidence to remove her. But I think you could’ve worded that better. Part of me feels like that’s wishing harm on her. And it doesn’t sit well

H: Youre a mother you dont ever have to deal with those thoughts because you could be the A of the relationship and they'd still never take custody from you but if it bothers you that much you dont need to deal with it anymore

M: I’m not saying that. I’m saying the way it was worded worried me. I care about the both of you can’t you see that? I love you both.

H: I dont know if I want to be in a relationship who thinks I want harm to come to my daughter

M: I want to be there and do my best to support. But I’ve never been in this situation and I’m trying to do my best. If there is anything you need or recommend to me for me to be better please tell me.

M: I didn’t word that the way I wanted to and i am sorry. I just want to help support and be there for both you and B because I love and care for the both of you. More than either of you could know

H: I love my daughter to the point i almost took my own live curb I couldnt see her and you really think I want to see her hurt. If I could take all the pain from every bump bruise scratch scrape and sprain away from her anf take the pain myself I would in a heartbeat. But you as a mom with a non existent father figure to your child will never understand the difficulty of being a father in a world where a mother can do anything and get away with it and the father still being the one who loses custody. Make look up some stuff on mens mental health and take a look at why so many men kill themselves. It’s because the system doesn't give a fuck about the truth and so men end up losing custody of their kids to women who don't deserve to even see the kids.

M: I can’t understand that. I’m not the father to my daughter. I’m just her mom. I’m trying to learn to do it all on my own. But I know she sees you and cares for you. My intention wasn’t to make you feel like a bad dad. It wasn’t to make you feel lesser than. I’m trying to do my best to understand you and your situation. I’m putting in the effort and trying my best

H: You insinuated that I wished harm against my daughter and I dont. I have nothing more to say on the matter

M: That wasn’t my intention. I’m sorry. I already am beating myself up over saying that. I didn’t mean for it to come off that way at all.