So. My story is extremely long and I won't bore everyone with the details. Ive been with my significant other on and off again for 2.5 years. I could never really pin-point his behavior towards me and his constant splitting, but I just recently discovered that he is suffering from BPD, which has been a huge relief.
My/our current situation. He's had some significant stressors in the last few months and is very worried about his future. To make a long story short, he failed an important exam in medical school, and has to take a year off. He seems stuck in a rut of feelings of failure about himself and cannot break free from the intense fear he's been feeling. He can't face the school or anyone from it. He says that he is "scared and unsafe alone", but scared and unsafe if I come around too. We had broken up in July because he shut me off and basically blamed me for failing the test and for causing his intense feelings of fear and failure. I hadn't heard from him in weeks, until he called me at midnight one night saying he had taken a bunch of pills and drank a ton of alcohol and didn't want to be alone when he died.
He didn't die that night, but since that time he frequently expresses regret over not dying, and states he has several "other" plans about dying that he's hidden from me. He even admitted to taking a whole months worth of beta blockers 3 days ago when I wouldn't stay the night with him. Oh I forgot to mention -- he's been seeing a therapist 2-3x per week for the last month or two and has also told her about his suicidality. He had another suicide attempt in 2005 and was committed to an inpatient hospital. He said the place was horrible and made him "way worse", so with his recent threats/attempts, he told me, his friends, and the therapist not to call 911 because if we did that would "officially set him over the edge" and he'd find a way to do complete it as soon as he got out.
So that's where I need

! Im tired of the games and the emotional strain this has put on me. I hate feeling like he's going to die at any moment, but also feeling like it would be "my fault" if I were to call the police/911. I honestly feel like a lot of his threats are pleas for attention, but I've honestly had enough.
Last night I went over to his place to spend time with him and try to be a comfort but within an hour it turned into a manipulative psychopathic roller coaster. He'd only be happy if I gave him what he wanted -- sex, drugs, alcohol -- and when I told him I didnt think that was a good idea, he shut off, started giving me the silent treatment, and said "sorry for ruining your night, I know I'm a loser and keep ruining your life, just go home its better if you just leave me here alone". UGH! He then started drinking a ton of liquor and started getting verbally abusive, so I did in fact leave. He then texted and called me a million times saying how he just needed me to come back and hold him and that he'd be "good" and wouldn't cause anymore problems. He made me feel that if I didnt go back, it could be his last night and I was the worst person in the world... but I honestly could not go back to the drama because I knew it would never end. What should I do? Is there anyway to have a civil conversation with him or should I just leave him alone since Im an obvious trigger to his stress?