Am I being unreasonable?!?

Ok, so my boyfriend of three years texted me today saying we were going to his families this year for thanksgiving and seeing his friends after. This is complete news to me, we’ve always spent it at my families and this year my brother and sister in-law + their kiddo will be in town. I’m not annoyed he wants to spend the day with his family I wouldn’t mind if he went however I find it so annoying that he waited until the last minute and then tried to unilaterally tell me what the plans are. We’re already supposed to go down there this weekend I thought to spend time since we wouldn’t be at Thanksgiving there. Am I being unreasonable? I don’t want to spend the day without my family.