OK, I guess I had misunderstood some things. I wasn't aware that you knew for sure that they planned a meet. If that's thecase, I understand the breach of trust, especially since he did not tell you about it, he should have.
I also did not know you wrote the letter. I thought you told him (verbally) roughly what should be in it and then he wrote it.
I do understand your feelings of "he's just checking the box" and "he's just doing the bare minimum". It's frustrating because you're wanting him to do so much more. I guess what I was trying to say earlier with cutting him some slack is not so much about accepting his mistakes and breaches of trust, but more about not pointing out to him what he's not doing constantly. It's more about patience with him trying to figure out how he can wow you. You have every right to set boundaries and enforce them. Hope this makes my thoughts a little clearer.