HEy Muldler- I know this is an old post that sounds done and dusted, and by the way i didnt read all of it cuz i guessed from skimming it was kinda private - but I just wanted to say summat about your opening remarks.
This is the way I read it.
Your "Couple" pals kept banging on and on at you to go on holiday with them, and sounded incredibly insensitive to your feelings about being gooseberry, and quite frankly i am not in the least bit surprised when you'd had a few drinks you put it to them in a more blunt fashion.
What did they expect? Mr Nice Guy to meekly go along with their wishes, ignoring his own feelings on the matter? Gosh, thats not a very even friendship, the scales are a bit tipped by the sound of it.
Its about being assertive, not submissive for fear of offending friends. Sometimes you gotta call a spade a shovel to get the message across.
That's all i'm gonna say.