My ex girlfriend betrayed me, can she come back to me ?

If you've been broken up for a year then she has a perfect right to get with whoever she wants. This isn't "betraying" you, its just her moving on with her life. I'd say that the chance of her and her ex working out isn't great. He hurt her once so he'll probably do it again. Still the chance of you getting back with her sounds slim. You've been broken up for a year a she is getting with someone else. Even if things don't work out with the ex I suspect she'd just find someone else.

Just move on with your life and look for someone else. If she breaks up with the ex and sounds like she might be interested in you again, then fine, you can try to make it work at that time, but this is very unlikely.

If she's clearly moved onto the point of wanting someone else, thinking about you is NOT a sign that she can come back to you. I still think about my ex's in regards to memories, they've helped shaped me for who I am today so I don't have full regrets regarding all of them.

However, you must move on your self, waiting and hoping is only going to leave you upset or jealous.

If you move on from her to someone else and she wants to come back to you, than from there you can decide what you want.

Let her be happy, and let her go my friend.

Yesterday is history, tomorrow is a mystery, but today is a gift, that's why it's called the present.