I Am Confused About My Relationship

I am in my longest relationship ever... The guy is funny, and smart, addicted to cuddling and kisses (totally not a bad thing) but also distant and doesn't know how to support me with my depression, which really forms a big barrier between us because I don't confide in him. He doesn't know what to say when I tell him about how I'm feeling, and then he feels bad he cant't help.
An old friend and I have been catching up, and he has not been able to be with anyone else, even after two years, because he loves me and he's still emotionally attached. I love him too. And I want to help him... he has really bad depression and has been lowkey contemplating suicide. I want to be there for him, like I haven't been before. I feel guilty about it, because I'm having doubts about being with my current boyfriend, but I want to stick it out. I don't want to be squirrely, push people away, or leave him for someone else. I'm his first girlfriend. I don't want to break him. Leave what I am familiar with, but disappointed, for someone who has proven they'll do anything for me? When I am worried about the well beings of both guys?

Please, no hate. I just want to figure this out...