It's normal to have fluctuations in desires, and it sounds to me that your location is partly whats upping the sex drive so dramatically. I personally don't enjoy sex much (don't get an orgasm, plus it's physically painful for me), and have only ad sex with my husband; but my fantasies, past and present, change sometimes for months at a time. Even though I generally hate sex, I tend to want it with those I can't have (I don't act out on this as I'm very committed to my marriage). I rarely have sexual thoughts towards women, but it does happen sometimes, almost always in spontaneous phases, like a couple months at a time (once again, I don't act on it), and then it goes back to my norm. The only times that I would have done just about anything with anyone was when I was in a remote location for an extended period of time, with relatively few options.