"Quite a few gays have been involved in heterosexual marriages."
This is unfortunately true, and usually because of societal and familial and theological pressure that makes Gay people hope that getting married to someone of the opposite sex with somehow "cure" them. There are also lots of men who do not identify themselves as Gay (which they see as a cultural label) who may have girlfriends or wives and even children ... and still occasionally have sex with other men. In the Black community such men are perceived to be on the "Down Low."
In any case, it's irrelevant to the issue of pedophilia. The majority of child molesters were themselves sexually abused when THEY were children. Sexual orientation has nothing to do with it.