Husbands friend

Last Sunday My husband and his best friend were watching a football game at our house. We all had some drinks then we started talking about a three some we had in college. One thing lead to another and my husband said he would like to watch his friend fuck me. We did and the sex was awesome he rocked my world. The friend by the way is married to a girl that was one of my co-workers. She calls later that night and asks if her husband was really watching the game at our house. She explained she thought he was cheating on her because she tried to have sex and he said no and got in the shower then she tried to get in with him and he had scratches all down his back. I told her he was at my house and my husband and him were wrestling so that could be were the scratches came from. I feel terrible but, my husbands friend and I have had sex twice this week without my husband knowing and I don't want to stop I love our sexual connection.