Originally Posted by JustAGirl
I didn't believe it was my responsibility to teach others how to treat him, and he resented me for many years - even after our divorce.
I'd love to hear about your experiences with triangulation and how you dealt with them successfully.
I'm racking my brain trying to think of examples of triangulation in my own life, and coming up quite astonished that I can't remember ever having been put in this position!
But for the first part of what I quoted, I think we teach people how to treat us, by how we allow them to treat us. Your ex wasn't a child and you weren't his mom, so it's not your job to tell people, even if they're your friend, how to treat him. Especially if that friend is also his roommate, then he needed to learn to communicate with her, by himself. But by the sounds of it, he also didn't communicate with you very well, so that's all wrapped up together.
Hmm, upon thinking a little harder, I wonder if I don't sometimes do this myself though, when it comes to my step-daughter. She's 16 now, she was 13 when I met her dad, and I've never felt it was my place to "tell her what to do" because she was already fairly well established "as a person" and I didn't think she was going to take some new chick (who was already taking over a lot of her dad's time) also trying to act like her parent. But I can think of a few examples early on where I would ask him to tell her something rather than telling her myself. I think that was also wrapped up in "I don't want her to hate me" which I don't normally care about with random people, but seemed to matter a lot with the daughter of my partner. I'm a lot more comfortable with her now, and more comfortable in my role (whatever it is) and definitely a lot more comfortable saying "this is my home, and when you come stay here, I have certain expectations."
I know that's not really what you asked, but maybe it helps to have a little insight "from the other side." And from the other side, having grown a lot in the past three years, my opinion is that it's the responsibility of persons A and B to learn to communicate without needing person C as a messenger.