I am thirty been with my wife for 15 years, I need a a girlfriend. ?

We've been together for 15 years and been married for 5. we have two beautiful girls and are planning a third, but our life is just not there anymore. she wants it kinda 'regular' I want a little more fun in the bedroom and anytime I try she gets bent out of shape,'I don't want toys, I want you' which is fine but I want some fun and excitment. I am admittedly a VERY ual person and have been contimplating finding a girl friend that would be completely seperate from our life. no phone calls no address no last names...Probably over the internet or with a disosable phone. Am I going way overboard or out of bounds, I understand about adultery and all that but I want to do this because I love my wife and kids and dont want to split the house up over such a stupid thing, My question is am I being greedy, or am I making a fairly sane argument.