Most Helpful Girl
You don't. That's up to her to decide if she would want to settle for less with a cheater. Besides you didn't even confess yourself and it probably wasn't the first time you cheated.
If she actually caught you in the act of having sex with another girl, no one gets over that. It's one thing to learn about getting cheated on but another to actually walk in on that.0THIS IS NOT RELEVANT ANYMORE