If he’ll cheat on his girlfriend with you , then he’ll cheat on you with another girl. Because once a cheater always a cheater since that’s one of those really hard habits that guys develop & that never seem too outgrow. You can’t fool yourself into believing that you’ll be that only girl that is going to be able to change him from his old ways. He might be different for a little while but he’s going to start to revert as soon as he sees that your trying to change him. So hunny, save your time & energy for some other asshole that actually matters.