And Lee - I know it sounds stupid, but way too many women can see you asking for sex as you not wanting THEM but just sex - dumb, huh? -when what you really want is to feel LOVED by her. So try telling her "when you don't want to make love with me, I feel really unloved and rejected".
Also - where's she at with her thyroid replacement? Is she back to her old self in all other ways yet?
