Why do men and women cheat on their partners?

There could be several reasons for cheating on a partner. I think man cheats for fun. He likes to explore new experiences with new women. He may cheat on a nagging partner. He may cheat on a sexually not so interested partner. If he comes across irresistible female. Financial problems etc... Women may cheat on when the partner is not talking enough with her. Poor communication. financial factor. sexual inability of partner. When the partner is not at all appreciating her talents and some one else is appreciating. Meeting a irresistible man.. That is all I can think of, now your views please...