I told my friend to walk away from a relationship, and he’s planning to, but now I have doubts about my advice. Did I do the right thing?

Sorry for the long read. The details are essential.

I have a very close friend M(50+), whom I have known since elementary school; he has had many bad experiences in relationships, including being cheated on, so he is always on edge when entering new relationships.

We’ve always told him that the women he’s dated weren’t quality people and he needed to look deeply into those he’s attracted to.

He started dating a woman entirely different from his past types, which was refreshing. They have been in an exclusive relationship for months, which is excellent!

However, she has a few male friends, which leads him into a spiral of fear and anxiety, thinking, “here we go again.”

We told him that even in a relationship, you could have friends of the opposite sex as long as you are open to communication and work with boundaries with your partner for those friendships.

But there is a situation that caused us to pause. She has a childhood friend with that she reconnected during the pandemic. During this time, they went on many trips and road trips together and shared a room. She explained that the relationship has been entirely platonic and that she is looking to continue that friendship and also to continue to do things they did with their friend while in a relationship with him.

My first reaction when he came to me was that if you trusted her, then continuing a platonic relationship was ok. Though I did agree that the activities may be beyond acceptable boundaries for what even I would consider my partner doing while in a relationship and that the two of them come to a compromise.

He came back downtrodden. She advised that what she had with this friend was purely platonic and was normal and healthy, so he just needed to trust her, so, in essence, no compromise.

I was still on the fence. I understand the defensiveness of being asked to shut down a friendship potentially, which no one wants to ever hear from their partner. So I was going to suggest a wait-and-see approach, knowing he hates that, but he needed to give her that chance.

Through a mutual friend, it was discovered that she wanted to date and have a relationship with this friend. She used platonic friendship and took these trips to entice him to start a relationship with her. The male friend only wanted company, so no ties came of that, and it remained platonic. If they were ever friends with benefits, that’s unknown.

Considering this, I told him that he should end the relationship. To have been lied to about the start of the friendship doesn’t set the stage for a trusting relationship. Furthermore, to say to him that she loves him and he means everything to her but being unwilling to comprise this relationship makes those empty words in my mind.

I was sure when I gave this advice, but I now have doubts. Any thoughts? I want to stop him if I have led him down the wrong path and live with the guilt of denying him some potentially wonderful.

Did I do the right thing?