My metamor showed up in town today unannounced to take our partner out to lunch. Normally, this wouldn’t give me a second thought, but their relationship is long distance—he lives about four hours away—and they already spend one of her two weekends off a month together. She was just at his place two weekends ago, and I know she told him that she wouldn’t really be able to see him in November.

Right now, my partner is out with him because, as she said, "Well, he’s in town, so I want to see him." I feel bothered because she only gets two weekends off a month due to her work schedule. Usually, he gets one weekend, and I get the other to spend time with her. Now it feels like he’s encroaching on my time by showing up without letting her know he was coming.

Am I just being insecure, or are my feelings about this situation legitimate?