My mother in law moved in with my wife and I a couple years ago when her house was foreclosed on. We had married under a year, and 24 years old, while MIL was 43. I always thought she was attractive, and have fantasizes about her. My wife was out of town last week, first time I had been at home with MIL only. It was instantaneous, we were kissing and clawing each others' clothes off. It took almost two years, but now we know we want each other. And it is so sensual to think that I am penetrating the womb that my wife came from!