How to back out of a situationship if I now don’t want to be in one?

Context: I (25F) met this guy (26M) a month ago when he was travelling in my city. We hung out for a few days and hooked up. I originally saw this as a travel fling and didn’t plan on seeing this guy again after he leaves. However, we kept on texting daily after he left and he seems to be directing this to a dating direction. He is coming back to my city tomorrow to stay for a month and we are going on a trip next week. Now, originally when these plans are made, I was just seeing this as a casual dating thing. But now after texting daily for a month, I feel emotionally invested and I do not want to be in this situation if we are not officially dating. I do not want to continue to sleep with him without being in a relationship and going on a trip seems very coupley.

What should I do in this situation? I can’t back out of the trip now and I do want to go, but I don’t want to be doing coupley things in a limbo. I don’t know what to do cuz we already hooked up before too. Thanks for your help!!