Most Helpful Girl
If he's the kind of guy that would cheat, it's hard to say whether he'd feel genuine remorse, or if he was ever in true love. The most likely response is that he'll chase her with a sob story like the anonymous user said.
Cheaters don't like to get caught and lose their stability. Sex on the side isn't nearly as fun for them if they don't have their good faithful woman waiting at home, so they'll do anything they can to get that good woman back. It doesn't mean he's sorry he did it, it means he's sorry he got caught. It also doesn't mean he won't do it again. In fact, if she lets him get away with it, he probably will. If she never takes him back, there's a better chance he'll live with regret for a lot longer.