Liz, I think the question was much simpler than you made it. It was "can YOU" do XYZ on such and such a day.
The answer is "no". You already had a commitment.
It is not detachment to think that, in order to answer that question, you have to track your AH down, verify his schedule, get him to answer the phone, then get him to give you an answer or not, or get his answer and wonder if he will actually do what he said he would do, or wonder if his voice sounds like he is drinking and may not remember what he said, or any of the many permutations of the above.
I don't understand what you are getting, under the surface, from this relationship. There is something compelling that pulls you into involving him in your thought processes and your activities.
It's almost as if instead of being co-dependent and trying to get loose from that, you are doing a similar struggle with being detached, and staying equally attached in the process.
You have a couple more years until your son is off and flying his wings solo into adulthood. From my experience raising 5 teenagers, now is when he needs to be learning to use his own resources more and more with less and less supervision and more and more trust that he can handle it, and, if he has a problem, he can handle that, too. Now is a good time to start imagining what you want to fill that void when your son goes forward with his own life. Life will reach out toward you when you do.
For me, having left a marriage at age 62, I wish very much I had done it a decade sooner. Starting life over at 62 is way harder than at 52, or 42.
Imagine yourself without your son or your husband. What would your life look like? What do you want it to look like? Just you.
If we fiddle while Rome burns, eventually all we have is a burnt fiddle.
Time is moving on, and I care about you, and it seems that you are circulating in the same circle of reasoning now since we first met here 2 years ago. I hope I've not been too blunt. Said with concern and a hug, take what you want, leave the rest.
ShootingStar1