You already made up your mind you can't cotinue with her . . what else do you want usto say nah??
Anyway, this kind of a situation is the one you have to decide solely how to tackle, what she did was bad, very bad, but . . . we all have our faults, i'm not excusing her, but maybe she was going through some difficult times

It all goes down to
how long you've known this person how much you trust them, if you think you could eer trust them again, if you can put what happened behind you and start afresh, if she hurt you too much that you can't see yourself being more than casual freinds with her,
You have to think seriously, putting all the mentioned into consideraion . . whether Nairalanders think you guysshould remain friends or not, at the end of the day, you're the only one that knows how you feel and what you're capable of doing and not doing