Most Helpful Girl
You gotta just forget her and move on. You messed it up and she moved onto someone else. Affairs hurt all involved, just don't do it.
Most Helpful Guy
Don't waste your time. She's your ex for a reason... trying to get back with someone is almost never worth it. I never went out of my way, and several of my exes wanted to get back with me. I regret the one time I actually gave one of them a second chance. You need to move on and find someone new, and remember not to cheat.