You didn't make her cheat. She had a choice to or not to. She chose to. The question isn't a matter of percent, but do you want someone in your personal space that you know you can't trust to be loyal, faithful, and true? Why do you want her back? Is it because you feel guilty, like you should have done something different or weren't BP then she wouldn't have stepped out? Is this truly something you can get over, not think of again, and move forward from?

If it's guilt, then it's the wrong reason to stay. Your self esteem and trust have been broken. Make sure to see your therapist or get into therapy if you aren't. Don't internalize the blame because that will harm your chances at reconciliation and at moving forward, whichever you choose.