SEX HELP

I am 39, in shape and happily married for 17 years to a beautiful & sexy women, we have 2 awesome girls.
This sounds great and it is but I still have 2 problems,
#1- My wife and I have sex 3 to 4 times a week, and I still find the need to playing with yourself, spanking the monkey everyday, is this normall, is there something wrong with me or do I have a sex "overdrive". please help.
#2- I really enjoy the sex that my wife and I have, but she will not let me go down on her, any ideas on how to change this.
Thanks JJ39 Tweet