My ex did something similar. He said we were “on a break”, went to the bar & ran into a female friend and they made plans to “hook up” that weekend. The weekend came & she changed her mind, so he got back with me. I said, “So if she had met up with you we wouldn’t be here right now would we?”. His response: “Well it didn’t happen, so it doesn’t matter”. We broke up a month later.