Let's leave aside specific counter-examples for a moment - like one partner cheated because they thought the other partner cheated first, or something.
In general, exceptions aside... People who cheat, do not need a good or bad partner to cheat.
The quality of their partner is not usually relevant to the cheater.
The cheater cheats because they have a problem with monogamy, not with their partner.
If you don't understand this, then if you're cheated on you may forever question yourself wondering what you did wrong, or what was wrong with you.
Now sure, there are counter examples - but I think in those cases, the issue is that the person was driven to cheat - for example the wife stops having sex with the husband, won't go to counselling, refuses to admit there's a problem.. and this drives him to cheat and seek sex elsewhere.
Those cases tend to be rare, but in those cases the women make the man into a dog. (Or vice versa.)
I'm also a magnet for this Crap. 90% of girls I dated either cheated on me or wanted me to physically beat them and mentally abuse them. As a full time Hero/Gentleman that wasn't going to happen.
I love a girl who enjoys communication and the word Faithful lol. Sadly I attract the opposite, so I had to change a few things about myself, an am now attracting better girls that don't crave getting abused but I still attract cheaters lol. :P