So, my LTR told me today that she met a guy that's an old colleague from an old job that she used to work at hand hung out with in a group, they talked about having lunch together, just the two of them next week and she told me about it. I just said "all right, have fun on your lunch date" but she could sense I was upset or at least convinced herself of that, which means I broke frame.. Then she told me that if I'm uncomfortable with it she won't do it, to which I answered that she should and that I don't care. This turned into somewhat of a fight and she said I was "questioning her". Also, they work in completely different departments so they will never work together.

What do you guys think? Should I accept this? Have you had any similar experiences?