BF 32M told me I wasn't invited to their Christmas gathering

I've been dating my BF[32M] for the past 2-3 years. So it's not like it's a fresh new relationship.

Yesterday he told me what days their family was having their holiday gatherings and one of them fell directly on Dec. 25th and that I wasn't actually invited to that one.

I work in an industry that is open 365 days a year so a few months ago I had to work out with my other coworkers on who would get what holiday off. Because we all have to work on days the rest of the country has off, we all more or less pick our most desired and least desired holiday to have off so that it's more fair. Since my BF is automatically off on Christmas we chose that day for me to ask off. So it's not like he didn't know that I would be expecting to spend Christmas Day with him. I ended up getting approved for that holiday off and scheduled for the other holidays.

So when he told me he would be gone most of Christmas Day anyways to go to a gathering I wasn't invited to I just felt really upset and left out. A few years ago I moved halfway across the country with him so my family isn't here but his is.

Granted this gathering isn't really even his family. It's the family of his moms new boyfriend she started to date within the past year. So in [my] opinion he as a grown adult really doesn't need to show up as a +1 to the family gathering of their equally adult parent's new bf. But maybe I'm just being salty. AFAIK the only actual family member of his going is his mom.

So maybe I'm just disappointed I wasn't included as a package deal with my BF or that my BF would pick hanging out with his mom's BF and his family that he doesn't even know over spending it with me after I went through all the hoops to get the holiday off in the first place.

I'm sure I'll be made fun of because I'm a grown adult myself but I've always been included and spent time with my ex's and their families. Maybe not to the level of "I expect to be invited to this wedding you're going to and we've only been together for a month". But just general gatherings either we both were invited or we didn't go.

I'd probably care less if this gathering wasn't directly on Christmas day but it is and it'll probably take up most all of the day.