I suspect that most run-of-the-mill cheaters are not the evil users/addicts we on our high horse would like them to be. Most are just humans doing what comes naturally to humans... which is sex/love. Honesty is acquired. Cheating doesn't have to mean that you're using someone, or addicted, or lost interest in your partner(s). I think it usually just means that the opportunity presented itself, it was hard to resist, and you did the wrong thing.
I hope that cheaters can be redeemed. We're close friends with this couple who cheat on each other and have been wanting to convert them to poly for a while
They're absolutely fantastic people, have a great relationship, love each other very much, but cheat nonetheless. He's told me of his fun lighthearted flings with his friend in Idaho; she's tried to get me into bed several times. Each begs me not to tell the other in the same language:
"He/She wouldn't understand. He/She is jealous."
Except, they're not. They couldn't possibly be unaware of each other's dalliances. His Idaho friend visits for weeks at a time. She hits on me at their parties. They BOTH make out with their totally hot poly unicorn live-in roommate at parties.
They just party and do what comes naturally, and then the real cheating is the covering it up and dishonesty. Result is a don't-ask-don't-tell détente.