Could you continue your Relationship if your Partner Admitted to Cheating?

Our relationship is only three months old. Through our conversations, we discovered that we’re related, yet we still chose to be together. Recently, she started acting strangely, and when I asked her about it, she admitted that her ex-boyfriend visited and they had sex. Now, the guilt is consuming her, and she feels unworthy of me, believing I deserve someone better. I want to give her a second chance, but I’m struggling to cope with the fact that she cheated.