Does it have to be a whole THING? Does he have to RESPOND? Isnt alright if i just say, "okay, thats your vacation THIS year, but NEXT year we are definitely taking our honeymoon."
Then repeat the next year or vacation. Eventually you work thru the stuff, in bits and pieces thruout the the year(s). But it doesnt have to be resolved THIS MINUTE. You talk a little about what it means to miss him on this vacation (or whatever), to do X alone, etc. You just chip away at it. But you recognize it as one of the major themes of your therapy and try to see whats behind it.
Then you sign up for match.com and wonder why all the guys, tho objectively okay-looking, perhaps even attractive, just dont appeal to you.