My (35F) husband (35M) chose to go see Taylor Swift with his sister on our 4 year wedding anniversary

As the title says, my husband spent our 4 year anniversary weekend on a trip with his sister to see Taylor Swift. He did not break this news to me that he would be doing this until five days before our actual anniversary. I told him that hurts my feelings tremendously but every time it is brought up he tells me that anniversaries can be celebrated anytime, it doesn’t have to be on the day of. So I sat at home alone and sad while he partied with his sister on the day of our anniversary. I feel like he is discounting my feelings by telling me that it was no big deal and that we can celebrate our anniversary another day.

I have been feeling upset about this for weeks. As an outsider looking in, what is your opinion on this? Do you think that what he did was lousy, or am I just being too sensitive?

EDIT: I want to add that I do know 1000% for a fact this trip was taken with his sister, so for those wondering if it was even with his sister it was indeed with her and not some other woman. I will also add that he did make it up to me by taking me on a trip to the Smoky Mountains.