Boy did you open up a can of worms here. lol
I dont think you can say that men or women are more or less likely to cheat. It is really a decision that each person has to make whether they cheat or not.
As to the whole thing about having as many partners as possible, as a guy I do feel that pressure from other guys to sleep with as many girls as I can especially after getting out of a long term relationship. Of course I don't do that but if I did I would be viewed as "the man or a pimp" or whatever its called these days. Crazy and stupid???
A woman on the other hand is often seen in a negative light if she does the same exact thing. I think it is a bunch of BS, but the double standard is unfortunately still there today.
I don't really care what a girl does before me, I wouldn't judge her on how many partners she had or didn't have.