Your ideal couples would be CSA all the way.
The only couples resort we have not been to is CN. I can tell you that for what you want you will want to go to CSA. Some of the reasons are that the night life at CTI and CSS is done at around 10:30CSA is the only couples resort I think with their own dance club. There are clubs in Negril that are awesome and you can get there and back again with a red licensed plate taxi! The beach and the tropical landscaping at CSA is dreamlike. The beach you can walk for miles on and there are parties all the time on seven mile. When you book be sure to get an atrium room second floor don't book anything else!! The food is great (I do not ever eat buffet food) as long as you book for reservations only for dinner. The spa and health club across the street is amazing truly amazing. Do book your couples massage early as well as catamaran cruise,and your dinner reservations. We honeymooned at CTI and CSA and we did a trading places at CSS. The only problem I had with CSA was that they were running at 96 percent capacity ( which is the norm for them) and we could not book anything when we got there however, after talking with the general operations manager ( she ROCKS !!!) we were able to do everything we wanted when we wanted. I will tell you that we are coming home to CTI in July. The reasons we really liked this resort is that the snorkling is better ( rougher waters but more to see no boats zooming by and scaring the fishes) the food is to die for! ( 8 rivers service and food is unparallelled) the Thai place is on the water and the food there is the same at Lemongrass however, at Lemongrass we were the dinner for many mosquitos since it is all outside and the last reason we loved CTI is that the staff treated my hubby and me like family.