I think that many women do not truly understand the role physical intimacy (with or without emotional intimacy) plays in a man's mental health. I know I didn't used to...but I've had some very heartfelt conversations with the various guys in my social group and now I "get it." It's WAY different from my own instincts about sex. Really counterintuitive.
I also know that when I was on antidepressants, I not only had no sex drive, I had a negative sex drive. Sex was unfulfilling, I couldn't focus, I felt nothing, and any pressure made me retreat into my own mind, roiling with resentment. So regardless of what someone else's mental health "need" was, if I had gone along with it, it would've been like those old stories about staring at the ceiling, thinking about the shopping list. Not good for either of us.
It's a tough situation, 9Iron. I hope the two of you can find your way through it -- I know it can be done if you both have the desire. It may just take more patience. I know....even MORE patience from you (I know what you've already been through) I'm sorry this is so damned hard.