Pink santa,
It sounds like a pretty unhealthy relationship, all around.
Do you two have any mutual friends? Have you ever known your bf to reach out to any other people?
You shouldn't have to stay in a relationship with your bf because he's threatened to hurt or kill himself. That only builds resentment within you! Years ago, when I was a teen, a bf of mine threatened to do the same. My bf was a major pathological liar (which is certainly different than a person who is stuck in major depression), but the effect on the person with them is similar. I was pretty irritated with him. Why he was so compelled to tell me these grandiose schemes, to pressure me into staying, out of guilt & pity didn't make him look more lovable to me.
After several months of baloney, I finally ended our relationship. That was what I needed to do for myself. I wasn't getting anything good out of the relationship anymore ~ it wasn't worth the drama.
I'd recommend that you be true to yourself and let go of your boyfriend. You aren't doing him any favors, by letting him guilt you in to staying with him. Tell him that you do care about him, and don't want him to hurt himself, but you can't stay with him either ~ it's causing you a lot of distress now. Gently recommend that he gets help from a T now. You just can't take the suicidal threats anymore...and you shouldn't have to.
From there, I'd recommend staying away from romantic relationships for a little while. Let yourself grow a bit. That will make you a lot stronger ~ and more comfortable in the choices that you make later.
Welcome to Psych Central!