keelium, I've been on both sides of the equation; being depressed and being the boyfriend of someone struggling with a disorder. While I can't offer any concrete suggestions regarding the prevention of your boyfriend leaving you, I do suggest that your boyfriend himself may be experience some level of anxiety/depression rooted in his inability to understand our depression and its attending behaviors plus his failure to help you. I don't know what kind of guy he is, but you do. Is he compassionate, self-centered, aloof, caring? I'm not making excuses for him when I say that he's human too and there does come a point in the dynamics of a relationship when love is simply not enough. I'm a romantic at heart and it's tough for me to say that.

I also know that we who are depressed begin to get very self-centered ourselves. I don't mean that as negatively as it sounds but the reality is, we tend to dwell on "our" problem at the expense and to the exclusion of others' problems. If your attempts to talk with your boyfriend degenerated into another argument it may because you slid back into the "need" mode instead of remaining in the "communication" mode in which you started. We've all done it and probably will continue to do it from time to time. If you have to go to the wedding with him, why don't you prepare yourself mentally and emotionally. Pulling the focus away from you and focusing on someone else in an interpersonal dynamic takes practice and for us, it's a herculean task. But it can be done. Try to engage others in conversation with your "radar" turned on and look for clues of the other person's troubles. We've all got 'em. Talk to the other person about "their" problem and don't mention yours at all. This takes practice and it's scary but it can be done. Hopefully by the time you go to the wedding, you can engage in conversation with your boyfriend and be able to be less needy, at least for a while. Try to steer the conversation away from "you" and to "him". The presence of the other guests at the wedding should be able to provide you two with enough "discussion material" if all else fails. It's not going be an overnight success. He's going to be suspicious and wait for the "shoe to drop" but at least it will be a start. It may not be a success and you may lose him anyway. If you don't try, you'll never know.

What I've related is based on my analysis of my own behavior and that of my ex-girlfriend. I hope that it is helpful to you.