*this can be applied to good looking guys too and I've seen it in practice (but muhhh he's not top 0.0000001%). No, he's good looking and fell in love with an average girl. I just happen to be a straight guy who dates women.

Aside from my personal anecdotal experience of dating hot women and average women, I'll add some logic in here:

So a beautiful woman (let's say top 10%) can get any man she wants all day every day, so she doesn't need to have a dual mating strategy; she can get a super handsome guy to settle down with her if she really wanted to. Either that or she finds good qualities in an average looking man that she just doesn't see in handsome guys.

Let's take an average looking woman. She can get sex from a super good looking guy but he probably wouldn't want to be seen dating her, so she'll have to settle for an average or below average guy for a relationship. Since she's not really getting what she wants out of either man, she'll try to get the best of both worlds. Since she can still find plenty of men willing to be in a relationship with her, she'll feel less of a restraint to cheat in comparison to a below average looking woman.

With a below average looking woman, it will probably be the same thing but less likely as she will have less men that are even willing to date her, so she'll have to hold onto whatever relationship she can get.

Conclusion: good looking women cheat the least while average looking women cheat the most.