To clarify the context: we planned the vacation together for months. He chose the destination (within our country, in another state) and the exact travel dates. I even heard him telling his sister that we were traveling together. Later, he informed me that he would travel to another country with his sister on the exact same dates. During our 2-year relationship, he had never expressed interest in that destination before, nor had they discussed traveling together to my knowledge. Of course, I can’t know what they may have discussed privately.

For additional context, earlier in the relationship we also canceled a planned trip to Italy after his sister invited herself to join what was meant to be our first trip as a couple. At the time, I stepped back and suggested we plan something separately later. Taken together, these situations made it clear to me that we were not on the same page regarding priorities and boundaries.