You are definitely not alone. I am in the same situation with my wife. She constantly knocks me down and loves to tell me what I don't do right or what a miserable person I am. After 15 years we sleep apart and speak only when needed. I was diagnosed with Major depressive disorder about a year and a half ago and I have just started to figure out why I let it get so bad. I come from a broken home and my father left when I was 1. I swore if I had any kids I would never leave them. I see now that I have let myself be emotionally abused and "dealt" with it for years to save my son that same damage (just to be replaced by different damage!). I am now stuck because depression has cost me my esteem, my job and my lust for life. I don't know what to do or where to turn.
Long story short (to late) just know you are not alone. Just reading your post has helped me realize, again, I am not alone either. So thank you for even putting yourself out there! It really does suck to be stuck at any stage in life but a bad relationship is the worst!!!