<human>: I'm sure I'm overreacting to this, and I just can't figure out why nor calm down about it. I have anxiety and it just won't let go of this.

Last summer we were invited by his long-time bachelor family friend to go down to Greece and sail around on his yacht for a week. For broke students, this was the perfect hot-holiday getaway, and it fell during our anniversary. We absolutely loved it, and had a great time. 

A few weeks ago, after establishing we were both working this summer and not getting away anywhere except maybe a trip at the end of the summer, this happens. We're sitting at the lunch table with his parents and aunt and uncle, and they ask what he's up to for the summer. He responds "Oh, I've been invited down to Greece to go sailing for a week." WAIT WHAT?? *cue double-take* I wasn't invited back, and he didn't have the decency to tell me. 

So I'm pretty upset, and we discuss it, and he says he'd just completely forgot to mention it to me and it's no big deal. The friend has been his parents' friend for 40 years, probably just didn't even think to invite me. Still pretty hurtful as we had such a great time last summer...

So now he's going away next week directly after his graduation, and I'll be sitting here at work, thinking about how I wasn't invited back on this holiday. And because they're all British (I'm American), it's too awkward for him to ask why I wasn't invited.

I'm so unspeakably jealous. This is the first time he's going on a trip without me since we've met, and we have travelled A LOT together to all sorts of places.

Talking about it isn't helping because he insists he's done nothing wrong (aside from forgetting to tell me) and this shouldn't be a big deal. But it is to me, and he is going, and there's nothing I can do about it.

So how do I come to terms with this???

Can you condense the text into three sentences or less?
<bot>: Boyfriend is going on a holiday that we went on last year with his family friend, but I wasn't invited back. Really hurt. What do?