No longer sexualy attracted by my partner
I'm a pretty mature guy who has a lovely, good-looking, partner. She's kind and generous and very good to me. The problem is that I've just gone off sex with her (but not her with me, because she has a high sex drive). I'm straight and I find women very attractive, by and large. I am monogamous. It may be that I just don't love her enough or even some medication I am taking might have something to do with an apparent decreased libido. It's now painful to spend the night with her because I feel that I am forcing myself to be affectionate. We are both touchy-feely sort of people and I do like intimacy, but at the moment seem to have lost interest in having penetrative sex with her.
What should I do?