My man...

So ive been with my old man for 2 years this may. We got together due to my brother passing and him being his best friend. We kinda consoled eachother. Everything was great. Then things started to change. I wanted to get a better job and join the navy. He told me if i bettered myself id want better. I reassured him that i only wanted him. Flash foward months later i brought up his pot and drinking problem. Like 2 cases a day and 6 blunts. A freaking day. I grew up in a house where that is tabboo. So i told him it made me uncomfortable. He understood but as time proggressed he dranj and drank and drank. I got sick of it bc all his money wemt to that and we were supposed to be building a future. We split last july. Stayed apart until 2nd week in seltember. I had another brother pass and needed him. We ended up back together and things were great. I again brought up the navy and he flipped out. He has some violent tendacies but has never hit me. He then proposed. He propossed december 1st. Well a few weeks ago we had a huge fight and i said we needed to calm for a bit then talk it out. He said whatever. Goes gets drunk and tells his mom if he cant live with me by his side the rest of his life he isnt leaving. He then took a whole bottle of zans. Was on life support for 13 hours. We were then fine. But hes gotten controlling. And if we argue he brings up suicide. He text me today and said due to my attitude and always fussing at him that if i continue he will leave. What do i do? I want to let him leave honestly because if i leave im scared he will try suicide again.. Help