A little background info:
The SO and I had a break and in an attempt to move on with my life I decided to entertain the offer to meet up with a long lost friend who I am aware always had an interest in me. Those plans to meet up fell through but was rescheduled. In an around the same time the SO and I rekindled. I mentioned the plan to meet up with this particular gentleman and the SO was not having it. He was in no way controlling, however, he did warn me that there will be a problem if I were to go against his wishes.
I guess he is fearful, but I am trying to relay to him that it will be nothing more than a lunch or dinner meet as I know my boundaries. SO responded with a simple "I know men and I don't want you meeting him." I do not want to disrespect SO in anyway, however, I do feel bad about having to break those ties with the friend whom I have known for over a decade over my SO's wishes (or insecurities?).