Kayla, I've stayed at both Moon Palace (
http://www.palaceresorts.com/Resorts/MoonPalace/Index.asp) and Secrets Capri (
http://www.secretsresorts.com/capri/). Both are nice.
Moon Palace is somewhat off to itself so you are not right smack in the hotel zone. But they provide transportation to the hotel zone if you want to go via a bus that runs about every hour. You have to wait 4 hours to catch your return bus but you can always take a taxi back if you want to stay longer or shorter. The other positive about Moon Palace is that you can visit the other Palace Hotels and use their facilities and eat at their restaurants because it's all-inclusive. The negative of MP for couples is that children are allowed here and sometimes can be annoying around the pool. I got nothing against kids, but, you may not want that on a quiet, romantic get-away.
Secrets Capri is a smaller, adults only resort closer to Playa del Carmen. It's definitely more expensive, but, well worth the difference for me. It's also an All-Inclusive with some really nice restaurants. This is a place where you can lay out by the pool or on the beach and really relax. They do a few activities around the pool but it's generally mellow and, no obnoxious kids (again, I've got nothing against kids, except obnoxious ones). It's not a happening night-life hotel but it doesn't sound like that's really what you're looking for. And, if you want it, you can always go into PDC. It's a short taxi ride into PDC which is a fun place to go. I find PDC much more enjoyable that Cancun.
Hope I've been helpful, feel free to PM me if you want.
