Oh goodness. I am going to be blunt here. Run. Fast.
If not, you are looking at a future with an alcoholic that is 10 years older than you. You will become his care taker, not his spouse. And that is not fun, it's not a relationship.
I know it's hurtful, and I say this all gently because I know it hurts. Keep that focus on you. If he comes back with suicidal threats, call the police for a well check. That will do two things, if he is serious it will get him the help he needs. If it's manipulative, it will let him see you mean business and won't deal with that.
No new contact = No new hurts.
Big hugs.