I think the state of your marriage affects your feelings about the gig/anniversary. I've been through this (several times, argh) myself. You kind of set markers in your mind: We'll have a lovely anniversary weekend that will give him us a chance to reconnect with what we're all about ... Same with other seemingly not-massive things, like birthdays and visits with friends, etc.
I belatedly reached the obvious conclusion that I was setting so much store by these things because I was working on the relationship, really hard if not altogether smartly, and had become desperate for credible evidence I was getting somewhere.
In my case, I was working on a relationship that didn't exist - trying to turn my reality into something else. I was in the marriage (the one I wanted) by myself - and I didn't like the real marriage we were both in. I still feel sad thinking back on it, but mainly for my idiocy in marrying that particular husband in the first place! Or second place, actually: I'd already made a similar cock-up.
I'm not telling your relationship's dead in the water. Only you know that - and you do, somewhere inside, but it might take more time and a different kind of effort to feel sure of yourself. I'm saying the anniversary/gig thing is a symptom, not the problem.
If you feel like hashing it out some more on here, I'd suggest a thread in Relationships rather than AIBU. Because, basically, YABU but it isn't the real story.
I hope you have a nice time anyway, whatever you end up doing.