Is it normal that my wife set me up to have sex with her mother?

My wife were visiting her divorced mother over Thanksgiving and started talking about her as we lay in bed. My wife thought that she would be much more laid back if she got some action. She then asked me if I found her attractive, I blushed and said yes. She smiled, put her hand between my legs and said that I was obviously turned on. She told me to get up, then she took my hand and led me out of the room. She knocked on her mother's door, went in with me following. She looked at both of us, said, "have a good night" and left. It was obvious what was implied, so we just kind of went with it. On the way home my wife she admitted to pleasuring herself listening to me and her mom through the wall. She also wants me to call her her mom's name when we have sex. It was very sensual being inside vagina that my wife came from, but it felt wrong too.