Most Helpful Girl
Most Helpful Guy
Ex's can get back together, but it's pretty rare because it's so hard -- especially when a breach of trust is involved in the break-up. The best way to recover from it is to say you're sorry about whatever you did and that you know what you did was wrong -- which means no self-justifying at all -- and that it'll never happen again. Even though this is probably the best way it doesn't have that great of a chance of really working.
I'm not sure what you did to breach her trust, but if it was a pretty big thing you're probably better off moving on and making sure something like that never happens again.