Need Advice Quickly Please

Help! I had a weak moment two weeks ago, and long story short, implied that it would be okay for exN to join me at a vacation cabin I rented this week ( a town we went to many times together on vacation), and although he claimed to be interested, after indicating that he wanted to join me, he hasn't contacted me since. In the meantime, of course, I've come to my senses and want no part of him. I assume that his lack of communication is just part of the whole N game. He likely thinks I"m just hanging on to my phone (now that I'm here at the cabin) waiting for word of when he's arriving.

Now, I'm afraid that he is just going to show up either at the cabin or at the beach nearby. Knowing that I'm dealing with an N, most likely textbook NPD, how do I react if he does show up mid-week or texts to say he's coming? I want to, for once, do this correctly. I don't want to demonstrate, in any way, that I am angry, afraid, or was even expecting him. - seems like all of my options just feed into the N's plan.

Please give me advice! I'm sad for myself that I got myself back into this situation, but for some reason it seems like the final act of a long and bad play, and I've decided to forgive myself that one slip. I feel closure and ready to move on, so I don't want to do anything to keep the dynamics going.

Advice?
Thank you!