Has he always been like it?
My dh has depression long term. Neither of us realised for a long time. It manifested in a lot of ways, no motivation to do anything, not able to get a new job as he couldn't bring himself to apply, bit obsessed with sex (think it made him feel better momentarily), he would either be really really unhappy about his job or our sex life or his hobby etc. There was always something.
It took years to work out that he would focus his depression on one thing and then say that the one thing was the problem that was making him unhappy, rather than he was unhappy and was blaming it on the one thing. Iyswim!
He is on medication now and has just started counselling. The medication has really worked! He did stop taking it for a while as he thought he was better but a few months later he started acting like a dick! He was convinced i didn't love him because of the lack of sex even though there was plenty of it. He was focusing on something to be negative about again.
He was awful to live with, like a black cloud walking into the room! He wouldn't do anything about it as he was so convinced that the only problem was that i didn't love him. Even i didn't realise for quite a while what the problem was until suddenly i twigged that it was probably the depression again.
Eventually i told him to either see the Dr and go back on the meds or i would tell his family about his depression. He went back on the meds and was a different person within a week!
He accepts now that it is the cause of everything and that he will probably need to be on medication for the rest of his life.