In the last year or so, I've noticed that the skin on the shaft of my penis is dry. I've always had dry skin. Everywhere. But it seems to have gotten worse on my penis, to the point where masturbation can actually crack the skin unless I'm sufficiently careful.

I've also noticed that after sex (unprotected... monogomous relationship for the last year and we both checked out fine prior to as far as STDs go) my skin gets especially sensitive, and if the sex is particularly rough or hasty (not properly warmed up so a bit dryer)... in those particularly rough situations I sometimes am very sore the next day where it appears that I have friction burn or something on the shaft.

Is there any STD that is known to cause very dry skin that becomes easily irritated to the point of sometimes even cracking? I don't have any other symptoms such as burning or sores with puss or anything like that, but this is irritating because I have to take like a week off to let things get back to normal or else I just keep re-irritating them...

Could I be allergic to something? Like her vaginal fluids?