I will say it now, and I will say it until those wonderful cows come home. Women are as loyal as their options and situation in life. If they are married or in an LTR with a decent guy and Di Caprio, Efron, Tatum, or Hemsworth came over to them and asked if they wanted to have some fun; they'd drop that bro like he was yesterday's newspaper. Maybe men would too (with females, obviously); but I am not too sure about that.
If you look this stuff up, it's not so much a gender divide as it is a personality divide. Men and women lie equally in OLD profiles and they cheat equally as much.
The personality traits that correlate with cheating are more or less:
- Poor impulse control, impulsive habits
- Thrill-seeking
- Validation-seeking
- Cluster B disorders like narcissism
- Previous or family history of cheating
And then there's the simple environmental cause. The more someone is away from their partner, and the higher their proximity to other people of the opposite sex, the more sheer hormonal happenstance and opportunism there is to cheat. Being on the same team as a hot coworker simply fires the body's sex drive up by itself, regardless of intent.