Sandals do couples only resorts in many caribbean destinations, and some of Thomson (Gold I think) do too

Keep an eye on Thomson Gold as, although they may not take children the hotel itself may allow children

That's sneaky then Glynis isn't it - Thomson Gold holidays are not cheap either

Best to check the hotel on the websites to make doubly sure

Trish, thomson now do adult only hotels , they are under a new section called "couples" . Glynis is correct in saying that thomson will not accept bookings for children in their gold selection but there might still be children because the hotel allows this.
We stayed recently at a couples hotel in menorca , i was really impressed with the hotel and holiday and would certainly look to stay in the same type of hotel if i was booking a package holiday. The cost of the holiday was £500pp for a week half board , i thought this was value for money taking into account the standard of the hotel, service and food. In fact it was worth £500 just for the peace and quiet!!