I had a boyfriend who said almost exactly this to me... He thought that our relationship problems lay solely with me and he wouldn't accept any responsibility for his part in our problems.

I went on anti-depressants
I started having therapy.
I started to get happier....
He stayed miserable.
Then we split.

So i know first-hand how horrible it is when things are like that in a relationship. It's not just you, he has his part to play, and by the sounds of it he's not doing a very good job at it by putting you down and making you feel worse about yourself..

Like the others said, therapy could help you. But if you start to get better and the relationship doesn't....then i don't know what else to suggest.

I hope things work out for you Coolbrock2