Infidelity

When I look at the topic of Infidelity it always surprises me how that when I think about it, a lot of people do it. People having affairs, cheating on their boyfriends and girlfriends, its around us all the time even if we don't know about it. Does this mean that it is more "normal" for us as humans to par-take in infidelity? When looking on the internet there are websites such as http://infidelity.com/ which are aimed at people who have had been through this and need support and guidence. To me this suggests that it is always going to be there within us, whether we like it or not. Films such as Unfaithful look at the Infidelity and the effects it has on people.