but if it is about rest, then come home a day earlier. you seem to think your dh will reject this idea though.
he can't have it all ways, tbh. he can, of course, choose to pay for a better class ticket for himself than his children. but why would coming home a day early form holiday be such a problem, if it is not about feeling superior?
that way, everyone wins - you all get exciting longhaul destination (some shorthaul destinations are exciting and interesting too, you know), you don;t have to give in to your misgivings about the different cabins, and your dh is rested for work. why would he need so much convincing? especially since the problem is finances, and this is the best solution for that too.