A man chose to go on vacation instead of coming to my birthday party, what should I do?

I am dating a man 20 years older than me. He has had three wives before me. He's single now. I've never been married, and this is the first relationship I've ever been in.

I will say right off the bat that I would never have considered him as a candidate myself. His interest and initiative was always there. And at some point, we started to twist. We just started dating.

And then this summer he went on vacation with his son, the decision to vacation was made when we were not a couple. I was sympathetic to that.

While on vacation he asked me about my birthday, how I planned to celebrate it, and I said that I wanted to celebrate with him, that I was waiting for him and missed him. He was happy to hear that and he promised me that he would come to my birthday.

But the other day he wrote me that the weather there was good and he was staying for two more weeks, and that I would celebrate my birthday without him.

On the one hand, thanks for the advance warning. On the other hand, I do not know how to take it? Is it worth it to continue this relationship?