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.
Please be more detailed in your case. What medication? Has anything happened in the past in the relationship? Despite how good she may look in many cases I have heard that some men who aren't interested in a woman despite her good looks coould not get in the "mood" to have sex.
"The Poor spend their money. The Middle-class bury their money. The Rich multiply their money"
I am taking blood pressure tablets and the declared side effect can be "impotence or reduced sexual desire". We have broke up a few times because of life-style differences , but we have come back together I feel that I am living a lie.
I am sorry for your problems. It must be frustrating. I think that the problem comes from the fact that you have broken up before. This causes stress and can disturb libido.
Also the medication can be a big factor. Since the side-effects are noted, that must be it. I would say you talk to her about it. The more you force yourself into having sex, the less you will want her.