I'm twenty-three and have been dating my girlfriend for about two years. About two months ago, we went over to visit her married sister who is having problems with her cheating husband. I have always been attracted to the sister, and she knows this. One day she calls me on my cell phone crying and asked me to come over. I kind of suspected she wanted me to go over for a reason. Sure enough, I got there and we had the wildest, craziest sex ever all over her house. I left just in time. We still have fun with each other secretly while her husband and my girlfriend don't have a clue.