If you truly love her, you won’t cheat. You won’t be able to. Love is partly about being willing to sacrifice for another. This includes not indulging in the impulse for immediate gratification. Love is so valuable, it supersedes such impulses because it adds more to our lives than indulging in any impulse ever could. So, as far as how to avoid it, decide what’s most important to you and hold tight. If you love her, you just say no to those other impulses.