Many partnerships are based around opposites even though at the outset of a relationship it is common ground that we focus on. One person has certain strengths where the other does not and so it goes. One problem, and it's one you may have identified, is when both people in a relationship reach a low ebb. In your case it appears you carry something of a burden as your partner seems to appear highly reactive to the moods of those around him. As crises occur he is affected negatively and as you feel depleted so does he.
The low moods he experiences as a result of setbacks appear directly related to his perception of events and his role in relation to these. As such, I would suggest you come very close to the issue by mentioning his lack of confidence, and I might also suggest there are issues of self-esteem and self-worth too.
The problem with these issues is that they can become quite circular and a person who experiences them quite frequently leans on another for support, guidance, reassurance and positive strokes. In other words their emotional maturity isn't all it might be and this can result in high levels of dependency.
Ultimately your question is about depression but my feeling is that other things need to change a little for these low moods to subside. Problems are there to be solved - not always viewed as insurmountable hurdles. I may be doing your partner a disservice by saying this and I'm sure he has many admirable qualities, however in such a short space I'm really just cutting to the chase.
Sometimes the process of change starts with sewing a few seeds. Hopefully if your partner is self-reflective, has some measure of insight and trusts you, he may be able to initiate a dialog with you over (a) why he reacts in the way he does and (b) thinking of new ways to respond in more adaptive ways. It's not always easy and this is why people turn to therapists for assessment and advice - which of course is another option to consider perhaps?
Depression comes in many different forms and its causes and effects also vary. I wouldn't like to speculate about the future your boyfriend has, but I'm guessing he is relatively young and his low moods are connected with specifics? This is grounds for optimism but he really needs to break out of the cycle he's caught in before it becomes embedded.
Hope this helps a little?
Hi, there. What Jerry says is true and I want to ask if your partner is getting any help at all with this. The chances of getting through this are much higher if he is. He might need medication, but working with a therapist can help get to the root of the depression or at least the ways in which he deals with it. No, you don't have to always be the strong one.
I'd like to suggest the blog, Storied Mind, written by a guy who has lived with depression most of his life and has learned successful ways to manage it. There are all kinds of posts about depression and relationships, in particular, that you might find helpful, as well as comments made by subscribers. Your partner may also find it helpful.
Hang in there, take care of yourself and I hope things work out the way you want them to.