Me & my so have been having major problems lately

I did something w someone when we were broken up & we still haven’t gotten over that... every argument we have about it he says that he can’t live w the pain anymore or that he wants to die & stuff like that & I been telling him that I love him & that I’m there for him but he says that it’s not real.. I’ve been apologizing consistently etc etc...

I’m at a point where I’m concerned & more Afraid when he says those things...

I’m not giving up but I need help so do you think it’s okay if I tell his best friend about our situation & ask him to be there for him as well with out saying anything... I feel that my boyfriend also needs to be around people who love him so I’m trying to tell his best friend about what we’re going through so that we can all be together.