I am very confused by a situation
So I had a confusing encounter with my husband and his girlfriend; for background when they first began dating we asked if she would be interested in a polycule (girlfriend is also married and we are al poly) but she stated specifically she wasn't attracted to me. That was disappointing but I was happy to see her and husband together.
So one evening husband, GF and myself are hanging out, they start getting intimate and I ask if they would like alone time. That is when GF inviting me to join them. She said there would be no interaction between the two of us and we would just be playing with husband. I agreed but she went on to interact with me. I didn't interact back as I thought she had set a boundary, especially since she knew I was attracted to her and she had already rejected me.
After I had some time to think about it all I find myself feeling used. Like she made this boundary she expected me to follow, and I did, but she crossed it herself and it felt like a 'rules for thee but not for me' situation, and frankly I feel like I was a convenience rather than a person in the situation. Am I just too close to the situation or does this sound weird?