“If your friend isn’t OK with it, they’ll cycle through feelings of yearning, resentment toward you and their ex, and jealousy,” Heide says. “It will erode your friendship and affect your relationship with your love interest.” It comes down to how you view your friendship — only you can answer which is more important.
Similarly, what does the bro code say about exes?
Never sleep with a bro’s ex-girlfriend. If you are attracted to your bro’s ex, you shall not make a pass at her without taking his permission. If he wants you to stay away from her, you shall abide by his request.