Wife’s Best Friend

I’ve been with my wife fifteen years, married for twelve. From her teenage years she’s had the same best friend and when we first met the two were housemates so I got to know her pretty well over the years.
We’re all in our forties now and whilst I’ve always found her attractive nothing ever happened. She spent most of those years single apart from a few brief dates but met a guy four years ago and has been engaged for a year.
Six weeks ago we all went to a party where for one reason or another she and I spent the night talking, but more than that just looking into each other’s eyes as we did and as it got louder standing closer. We both felt it and as my wife and I left I said goodbye. To our friends and my wife it looked like a gentle kiss on the cheek between friends but our lips brushed and our fingers touched in a way that was so sexually charged I couldn’t stop thinking about her through the night.
The next day after work I went home via her house. She answered the door and just stepped back as I walked in and without saying a word we kissed. Softly at first then our hands were all over each other. She grabbed my hand and pulled me up the stairs and onto her bed. There was little foreplay. I was rock hard and she was soaking wet as I dropped my trousers, pushed her skirt up pulling her panties to one side before burying my cock deep inside her. I held myself fully inside her for a long pause, she gasped “just fuck me please” and I just went hard and fast until we both came. Recovering we spent the next hour licking, sucking and fucking every which way before agreeing it was crazy and had to be a one off.
I’ve been back every other day and just can’t stop. She’s the sexiest fuck of my life.