We've been together for 6 years. From the start I knew he had pretty bad OCD and was generally a quite neurotic guy, but I accepted this. We moved in together 4 years ago and things started getting worse. 95% of time he is a cheerful, funny, sweet, gentle person, he constantly compliments me and says he loves me and generally kisses the ground I'm walking. However, in situations of severe stress (and he gets severely stressed for pretty bizarre reasons), he gets in a state where he shouts at me, insults me in a way you wouldn't think he's capable of, physically makes me sit down or stand up, follows me around, either doesn't let me leave the room or tries to make me leave the apartment, mocks me, throws things. It's like he's a totally different person. It may last from 10 minutes to an hour. Afterwards he cries and cries and is hysterically apologizing to me for what he have done and I can see he's suffering.

He seems to realize he 'has problems' and 'is neurotic', but also apparently thinks that his behavior isn't outside the norm. Half a year ago he went to see a psychiatrist and got a small dose of paroxysine. I'm almost sure he hasn't told the doctor even half the truth and that he got a poor diagnosis because of it. He is also extremely reluctant to come in regularly for checkups and prescription refills, and takes from my pool of paroxisine instead (I visit my psychiatrist regularly). He seems to think he's fine and gets upset when I suggest he might need therapy.

I come from an abusive family, and have my own share of problems, so I understand that sometimes you can hurt others although you don't want to, because of your emotional state, but I also think I have difficulties with drawing a line and deciding what's normal and what isn't. I've been attending therapy for half a year now and recently my therapist told me upfront he thinks my boyfriend may be ill and that he desperately needs therapy.

He doesn't want to hear any of this. He has been attending therapy for years, mostly because his OCD and shyness, but he says 'it was a total failure'. Like I said, he gets extremely upset when I mention he's not well and that he needs help. I have no idea how to encourage him to try therapy. I'm afraid that if I push him too far, he might start considering me his enemy and stop sharing anything with me. I'm also pretty sure that if I threatened to leave him or even left and told him I get back only if he starts therapy, he will just break down and hurt himself.

TL;DR: My boyfriend gets aggressive when stressed, doesn't want to hear about therapy, my therapist told me his symptoms sound like mental illness, I have no idea how to help.