If budget is very important for 2 of your couples, it seems Europe may be out of the question. Flights are very expensive. Have you consulted a TA? I bought a book from Barnes & Noble about DW, and it gave a ton of info on different locations. I would start there. Fiji is beautiful, but I'm not sure about the cliffs, and it is very expensive to fly there. The Greek Isles do have beautiful cliffs, but again about the flights. The Caribbean may be your best bet.
What is "good enough" for him? St. Maarten, Turks & Caicos, Bahamas?? The Caves in Negril, JA is an All-Inclusive on the cliffs, and was voted the #1 most romantic place in the carribbean, but it is sort of pricey... I guess if he is holding up your decision making, then you need to ask him, "What is good enough?"
Good Luck, I hope BDW is able to help you.