My son is 22 and his wife is 20. About a year ago he asked if they could move in with me as my son had joined the military and he was shipping out to basic training and he wanted his wife and their new baby to have a safe place to stay. I am divorced and live alone in a large 2 story house, so I agreed. The first couple weeks were pretty normal. After he went away to basic things started to get obviously erotic. Even though they have their own bathroom, my master bathroom is larger and has a whirlpool tub. His wife would ask to use the whirlpool tub while I was in my room watching TV. At first I noticed little things like her leaving her thong panties in my bathroom or walking around the house in just panties and a wifebeater or a lace teddy that hid nothing. It gradually grew to her leaving the door to the bathroom open a bit and thanks to several mirrors in the bathroom I got a fantastic view from my bed of her naked everytime she did. I thought I was imagining her doing it on purpose until one day she called from the bathroom and asked me to bring her a towel. I expected her to be covering herself somehow when I took it, but instead she stood there naked and dripping. I was immediately aroused. I went back to my bedroom and was laying on the bed when she came walking out with the towel wrapped around her hair and naked otherwise. She asked if I minded her being naked and I assured her that I had no problems with it as long as she didn't mind me blatantly enjoying the show. She climbed on the bed and kissed me and one thing led to another and I fucked her. Later she told me she hoped I was OK with what we did. I assured her that I was. She told me she loved my son, but she needed sex and couldn't help herself. In the following weeks we fucked every day, but it was always physical, no kissing or "loving", just animalistic fucking for the joy of fucking. Things got pretty kinky after that. We got into some light bondage and spanking, throat fucking, nipple play and light tit torture...the list goes on. About a week later my son came home from basic and we had to go back to acting normal. After about a week he left again for 4 months of specialized training and she and I went right back to where we left off. After his 4 month trip was over he deployed to a non-combat assignment and will be gone for a year. Their relationship appears normal on the surface. He calls her regularly and they Skype. He thinks she is being totally faithful while he is gone. The flip side is I am in heaven. She is my personal slut. I get pussy anytime I want, a blowjob anytime I want and all from a hot, slender 20 year old that can't get enough. I feel bad that I am using my son's wife like this, but if it wasn't me it would be some other guy getting all of this free pussy, so why not?