I do not believe that you are wrong for how you feel about their “friendship.” The proof is that he had been cheating on you with her. That was your concern and you were right to be concerned. She was not a “friend.” That was a lie. She was effectively his lover.
He may have kept the relationship going with her because he was attracted to her and thought that he could resume a sexual relationship with her in the future. Or they had been having a sexual relationship all along. Nothing about their relationship would classify it as a friendship.
Typically, friendships don’t involve sexual relations. Once it does, it moves out of the realm of friendship and into something else such as “friends with benefits,” which is a euphemism for having casual sex with someone without a commitment.
I am also curious about how you learned that they were having sexual encounters via the phone and Internet. When you did find out, it seems as though you immediately spoke to him about it. You were right to ask him to “leave her alone.” Many people, at that point, would have ended the relationship. Asking him to stop wouldn’t have been an option for many people.
A concerning aspect of the relationship was when you expressed how uncomfortable you were with their continued “friendship” he, in no uncertain terms, refused to end it. He outright refused to end his “friendship” with her no matter how it made you feel. In other words, it didn’t matter that you disapproved of his having a relationship with someone whom you knew he had been cheating on you with. He didn’t care. He cared more about continuing his friendship with her than he did in continuing his relationship with you. He made a choice and it wasn’t you.
In addition, he then accused you of overreacting, claiming she wasn’t a threat and that he didn’t want her, all statements that you now know to be untrue. He was doing what he wanted to do and you had to simply live with it if you wanted to continue dating him. Perhaps that would have been the best time to end the relationship. The fact that he chose her over you was a sign that he didn’t seem like a match for you.
It seems like ending the relationship was the right thing to do. He was cheating on you and unwilling to give up his “friend.” What you wanted mattered less to him than what he wanted or what his ex-lover wanted. In relationships, equality is important. Whenever there is an imbalance, that is a problem. Hopefully, you’ll find someone who is worthy of you. Good luck in your search. Please take care.
Dr. Kristina Randle