I’m giving him an ultimatum

The last four years me and my bfs relationship has been an extreme roller coaster. We’ve literally been through it all. Honestly if you can think of it we’ve probably been through it. I’ve stayed. I know you’re think well she stupid for staying but I honestly could never see myself with anyone else. He’s my best friend but sometimes it’s like he’s also my worst enemy. We recently lost a baby and the arguing has gotten intense. He’s said some hurtful things lately and I’ve had it. I can’t take it anymore. He’s been through a lot in life (which I know is not an excuse at all) and I know if he got help and went to therapy he’d be so much happier and I really think it would help him with himself and with our relationship. He truly is a good guy. But I know I can’t force him and honesty it’s no longer an option for me anymore. I do not want to be with him unless he goes to therapy and tries to get some help. I’m afraid he won’t do it but I’m preparing myself. I’ll miss him to death but I can’t stay with someone who is angry all the time and doesn’t know how to express it. I’m crying just think about not being with him because again he really is best friend. I still don’t know what I’m going to do with out him if he says no but I know I’ll be ok. I also know his decision will show how much he truly cares about me. But am I wrong for this? Am I stupid for even trying to give him an ultimatum and just setting myself up for failure?