Can Cheaters Change? Not a chance!
Once someone crosses the line in the relationship (again, that line being different things to different people, but for argument's sake, we're talking here about the horizontal hora), it's like a seal being broken on a pill bottle. Though some of it may depend on whether it was a drunken fling or an ongoing stealth hookup with someone at work, the fact is that once that trust is compromised, the offender will have a hard time resetting the relationship to its startup condition. Even if the victim accepts the offender back into the relationship, the offender will be likely to stray again -- because he knows he's already gotten away with it once. The bigger picture, really, is the fact that he (we'll assume the cheater is a he; sorry, guys) cheated for a reason -- that something in his current relationship -- for example, one study showed that couples with infidelity issues showed greater dishonesty, arguments about trust, narcissism, and time spent apart -- made him explore other options. And that's ultimately what makes him prone to do it again. But...
Can Cheaters Change? Absolutely!
Just because someone has cheated in one relationship doesn't mean that he's always a cheater in his next relationships -- for the very same reason. In the relationship where he cheated, he was willing to gamble it away. So if he enters a committed relationship where he feels there's much more to lose, there's a less likely chance he'll want to risk it. Does that mean he won't, or that he couldn't succumb to the temptations of the tight-topped bartender? Of course not. Cheating certainly can make some relationships impossible to continue, but some infidels can indeed change -- that is, if he hopes to make other relationships even remotely possible.