The best holiday i have ever had was 10 days in Nairobi and the Masi mara without our son. We spent all the time saying - ahh, he would have loved that etc etc - but we had a lovely time and did many things that we may not have done if he'd been there.
Dont feel guilty. I'm sure they'll milk you for everything you have to make up for the guilt!!!
At the beginning of December there will be less kids around (apart from the locals of course) as they should be at school although the 6th and 8th December are fiesta days here. Bank hols to you and me.
For 'nice' places look at the Riu hotels, Gran Amadores, marina suites and the serenity apartments.