Thank you for all the replies and links so far.
This has to be one of the most difficult things I've faced. It is such an effort to find that position where I can just "let go" and "have faith", as someone (not here) told me to do.
I am a planner and detail-oriented. I have more than a Plan B, I have a whole alphabet. I consider all angles of things and prepare for all the possibilities, the what-ifs, and pre-arrange how to handle the consequences.
From that description, you can, I hope, get a feel for what a nightmare this looks like for me. I went on a roadtrip from hell with someone once when I was in college. They had no hotel reserved, no tools in the car, no AAA, no snacks, no idea where gas stations were, no emergency kit (in the Midwest this involves a first aid kit, blankets, candles, etc.), and finally...no printed map (just handwritten and drawn instructions).
Had I known any of this, I would have seen to it, but I was young and made the assumption that everyone planned like my family taught me. Boy, was I wrong. I won't tell the whole tale, but the result was that I never traveled with them again and that I saw to it that I did the travel planning or double-checked whoever did.
So leaps of faith are really not my style. And unfortunately, shifting our marriage to any flavor of this lifestyle involves just that. And worse, a lot of it involves that abstract category of emotions. There is no way to know beforehand all the triggers that could cause issues and no concrete way to plan for how to address them when they do.
I sat down and tried to write out some scenarios and situations and guidelines, but my husband was irritated. Aside from safe sex precautions, providing information on who/where/what/when, vetoing the use of our bedroom/house, and making sure the family schedule/time needs comes first (Dr's appts, holidays, birthdays, illness, etc.), he doesn't seem to want to agree to anything I propose, even if I tell him that the plan is a Stage One agreement that we will adjust as we go.
For example, I told him that I was not okay with "travel hook-ups", meaning no one-nighters while traveling alone, or any random stranger hook-ups for that matter, and he immediately took advantage of a noise from the other room (not anything that really needed investigation) to disengage and leave the room.
It is making me feel like I can have any compromise I want as long as it is his way.
If I have to give up some of what I want so he can be happy, shouldn't he give up some of what he wants so I can feel secure? Shouldn't he - if he wants to be with me as he says - be willing to accept not getting the "whole thing" if the result is keeping our marriage?
He doesn't want "a bunch of rules" and said "absolutely not" to any form of veto. He wants us to both be trusting in the fact that the other person wouldn't do anything to hurt the other, but if we don't lay those things out, how will we know? How will any of the SOs involved know what is okay and not okay if we don't?
I worry about the effects of NRE too, and being taken for granted. I already feel that way sometimes when it comes to his job, I don't need another person adding to it.