Ladies your help is really need

I am a 36 years old happy married to a 34 years old bbw with two lovely k**s. My dream is to share mu wife with a stranger but I have no idea how to let know about it. She is a very open lady sexually loves anal, and I am pretty sure she would love the idea. I really need your help for this one. Any,experienced couples or ladies can give me ideas.
PS: I ve noticed most married guys to bbws have thought about sharing their curvy jewels.