Is it normal that i want to share my shared wife with my half brother

I have been sharing my wife since we were dating at 17 our first mfm. We are now 42 and have always had a male that joined us.! I know it's not for everyone but it is for us! My question is ... Is it ok to want her to sleep with me and my half brother? He's very sexual obviously we are she loves the attention she loves going from classy teacher and mom to total slut in the bedroom.. I have a feeling even if we decide against it it will happen.! We visited him 4 years ago and I told him vaguely about our sex life that night I went in to get a sweatshirt and he was smelling her worn thongs I watched as he got off to them. I don't blame him I left them in site as soon as wife went downstairs.. It truly turns me on thinking about it and we just had sex fantasizing about it. My bride thinks that if I get called away to work that it would drive me crazy those two here without me. Let me also say we have not had many partners we just had a few that lasted years and also she's only ever played once without me, however I was on phone and had face time on another. If you would like to chat privately please leave it in your response... Thanks.