What would you do if you found out your partners’ friend was trying to convince your partner to break up with you?

My ex finally confessed to me that her so called girlfriend was trying to break us up and tried coming in between our relationship, which she accomplished but now my ex is apologizing to me and said she should of listened to me , cuz she now realizes her girlfriend is a toxic bitch. I told my ex she had her chance and she blew it. What would you do in this situation? Would you accept your exes apology or tell her to Fuck off?
What would you do if you found out your partners’ friend was trying to convince your partner to break up with you?
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