Ultimately that decision is up to you, but I would confront her and ask her about it see what she has to say. If she lies about it and you know for a fact, it’s true then it’s time to let it go because it’s just going to lead to heartache and devastation if you don’t but that’s not my decision to make it’s totally up to you as to what you’re going to do or not. I hope for your sake that it’s not true because there is nothing more heart breaking than loving someone and it not being reciprocated.