I have been married to my wife for 5 years and are in our early fifties,she was married before for nearly 20 years and has 2 teenage daughters.She divorced her ex because of numerous affairs and has told me he could never get enough sex.I get on reasonably enough with him when he calls to pick up his daughters,(who absolutely adore him and cannot understand why their Mum divorced him).Anyway my dream or fantasy is Jim(thats his name)coming to our house to pick up the girls and he says he wants a word with my wife in private,I go into the kitchen and they stay in the front room,(the girls are upstairs in their bedroom)After about 10 minutes I decide to go back in they are on the couch wrapped in an embrace and Jims hand is up her skirt playing with Barbs pussy,I shout what the fuck is going on?He turns and looks at me and tells me to fuck off,I like a wimp say nothing but sit down and watch them as he pulls down my wifes knickers exposing her wet pussy she opens her legs wider as he unbuckles his trousers and releases a thick erect cock a lot larger than my 5 inches,he then gets between her thighs and guides his bulbous head up into her gaping fanny,I watch mesmerised as he slowly begins to fuck her,I release my own stiff cock and start rubbing it as I watch his arse push his cock deeper and deeper into Barbs cunt,AS he speeds up my cock erupts and stare as he fills her with his hot spunk,they lay there in each others arms panting,its then I notice 2 faces peering from upstairs the girls had seen everything,Their hero Dad fucking their Mum and the horrible step -dad wanking.