Living with a depressed partner and becoming depressed?

[ChasingDreams]

My boyfriend has been depressed on and off the entire time I have known him and tends to have very negative and hopeless thought patterns, which I have struggled with, because I usually have a more optimistic view of things and people. After years of trying to convince him that everyone isn't out to get him and that there is hope, I've given up and started feeling hopeless myself... After I have a bad interaction with him (like he gets angry suddenly or starts talking about how bad things are) I can't shake the sad, empty feeling and obsess over it for days (or longer). It's severely affecting my job, because I can't focus and get anything done. The day will end and I've only finished like 1 thing from my to-do list of 10... I'm also finding myself having the same kind of angry outbursts that he has, but unfortunately at my daughter sometimes:(

Weekends are not something I look forward to anymore. It seems that the longer we are together, the more negative the whole energy gets... This past weekend was no exception... I was glad that he had opened up and started talking to me, because I know he had been holding onto a lot of stuff, but by the time he finished I was so physically and emotionally drained that I could hardly move... I was just sitting there staring into space and overwhelmed by the energy. The strange thing was that I noticed as soon as he left the room I felt better...

I wish I could find a way to listen to all his negative thoughts without taking them on myself... I know he really needs someone to talk to, but it is all so personal to me that I can't help but get upset. And then me being upset just makes him more upset and we go around and around>< I also find myself arguing with him, still trying to convince him that things are not as horrible and hopeless as he seems to think they are, but I know that useless...

I also know that I need to protect myself somehow, so I can help him without being sucked into depression myself (especially for the sake of our daughter) but I'm just not quite sure how to do that...