Looking back at some of your posts, I have no clue as to why you got or stay married.
The answer to your question is, YES! But, you already knew that, or you wouldn't have asked us to condone yor ridiculous behavior.
Technically, what you describe is odd and tacky, but perhaps not bad. What is bad, is the fact you two have already, "made a deal." I feel sorry for your wife. :redface: Seriously dude, just call a divorce lawyer already.
Would you be OK with your ex-wife fucking your brother? Or how about the two of them striking up a deal like yours while you were still married? If you answered yes to my questions, then I don't know why you asked yours.
Your original post did not make it clear that you are not currently married. The way you worded your question, it sounds like a hypothetical situation.