Men who have one fetish commonly have three or four others. When I was taught psychology we learned that the scientific terminology for this is that 'paraphilias cluster'.
So a man with a fetish for wearing nappies and cross dressing is more likely to have several other fetishes - such as exposing himself, or voyeurism, than the average man.
An obvious example is convicted child rapist David Challenor. His paraphilias included being a furry, wearing nappies, cross dressing and paedophilia. He raped and tortured a ten year old child while he was dressed as a little girl, and he forced his victim to refer to him by a female name which was part of his kink.
Challenor's son Aimee nearly became deputy leader of the Green Party, before it was revealed that he hired his father to be his election agent even though he knew about the rape charge.