how to help depressed boyfriend

I'm struggling to understand/help my depressed boyfriend. When he is not in a depressed phase, he is amazing, fun, friendly, smart, everything i could ask for. Recently though we've been having some problems, and i'm not sure if this has anythign to do with it... veterans day being today and the things hes told me about his time in iraq really are traumatizing and he's sai dthat when he thinks about it it makes him depressed. It seems elik when things don't go his way, or the way he thinks they should ideally be, he gets so unhappy- he said he gets depressed to the point where he cant deal with it and he thinks everyone hates him and everything just sucks... i know hes been through a lot and his family life isnt easy... a lot of arguments... he wasn't the most well-behaved in high school either and since his term in the military (he got discharged), he's back in college and he has said that being with me makes him want to do well... he's acing all his classes and trying to quit smoking, he prefers a night in with me to a night out at a party... he's really doing great for himself now and i try to convince him that he has improved bc he says he feels like hes messed up so much in life that its hard to look at the good things now. Does anyone have any ideas of how to talk to him or help him with this? there are bound to be dissapointments in life and when something big and tragic happens, i don't think i'd be able to handle it bc its so bad now and its just over a few minor arguments... i started to wonder if he's saying this just bc he wants me to feel guilty about leaving him (one of the arguments ended withg me saying maybe wed be better off apart) and if so, it worked... after our talk i told him if we broke up id be worried about him bc hes come so far... am i sucker??? i love him but its getting hard to... i feel like im giving too much and need to focus on myself and think of what this is doing to me... please help, anything helps.. thanks

funny, you sound just like my boyfriend, we just recently got into a fight because he was unhappy with somthing that i did, but i had a good reason for doing it. and he realized this the next day, but i guess what i have to say it taht it may REALLY, and i mean REALLY help him to go to a couselor, and get some of these feelings and thoughts out of him, they seem to be tearing him up inside, and once he lets it, it will tear the two of you apart, but it also sounds liek he's really willing to let it not tear him up, so ya'll are in coolege? see if they offer free counciling, i know my college's have saved me more than once, seriously, get him to try talking to somone who cna help him move on, it's essential, goodnight, and good luck