It's not really clear what drove you apart in the first place...lack of sex drive? Many people have a low level of testosterone, which is responsible for libido. If that is you, I'd suggest you try bio-identical hormones...it will change your sex life and give you the "urge".
However, it seems the issue is deeper than that as he is still in a funk after giving up his affair. Since he is the one who cheated, why is HE hurt? Just lack of sex? There is obviously much more going on with him. Often affairs signify there is more of a problem than just sexual desire. Unfortunately, there is no magic way of making someone love us. Getting thru to the real issue is the key....did he feel unloved by you? Or what?