To both The Flying Man and FIllness and fatigue: I've been in your shoes (nice ones, by the way, you have good taste in footwear) and actually had the misfortune of falling in love with someone with low self-esteem and - ach! - even married her

.
Please take this in the spirit it's intended, to help you as you go through this:
Get
Out
Now.
Really. Unless you're a trained psychiatrist or psychologist, someone like that can suck the life right out of you (not in a good way). Whatever you do/don't do will never be good enough, s/he will constantly second-guess your intentions whenever you make any sort of compliment, s/he will be extraordinarily demanding, clingy and a downright paininthea$$.
I know you're thinking, "But I can't do this to her. She's different. I can help."
Yes you can, no she isn't, and no you can't.
Learn from the mistakes of others. I wasted nearly a decade of my life on someone who's exactly like this, got nothing in return, and when it ended I lost over 2/3 of my assets.
There is absolutely NO up-side to staying with someone like that. Trust me on this.