Oddly enough we were having this chat tonight at a mates house. 1 girl in freshers ****ed some bloke on her second night, then got with 2 more in the days to come that I know of, allegedly told her bf and he had her back, she seemed very apologetic and I doubt she'll do it again, typical case of sheltered girl going to uni and going mental.
Another girl who seems very sweet and innocent cheated on her boyfriend of 3 years with someone else (who also had a girlfriend) several times across about a month, my mate then found out she'd cheated on him 13 times (!) including once when her boyfriend was passed out at a party on the same bed as him. Karma though, the guy got cheated on by his girlfriend who told him she'd kissed another lad, felt terrible and dumped him. No idea if she knows.
Another girl my mate went out with who is proper up herself (with not much reason to be, frankly) basically dates nice guy types who will stick with her no matter what then cheats on them with typical 'lad' types, once infront of her next bf at a club, and then about 8 times in magaluf, and again while they were at the same party. He's clearly a mug for having her back after she cheated on him right in front of him though.
And finally for some gender balance my mate used to get with (just kissing afaik) the odd girl when he was with his ex, who everyone told him he shouldn't be with her as he clearly wasn't into the relationship, but now he's with his new girlfriend they're really happy, he's not cheated in the 2 years they've been together.
I've said this before and I'll say it again, it's much easier to spot a guy who's going to cheat than a girl, and women are just as likely (in my experience, more likely, but this is likely chance) to cheat as men. Also the number of girls I've danced with/whatever in clubs who let you pretty much be all over them but then say they have a bf when you go in for a kiss is unreal, as far as I'm concerned that's cheating.