ditto. However I don't find that to be a dichotomy. God never seemed to be prudish about sex, after all He GAVE it to us. Ever read Song of songs? David, "God's beloved" had multiple wives, and had he been honest and not had Bath's hubby killed, He would have been ok. In fact the soldier himself would probably have given her to the King himself if asked.. Abraham traded Sarah out at least x2, and it wasn't until God decided to found a nation that He intervened. Ever notice God seemingly sanctioned slaves, concubines, and while thankfully times have changed some, women were treated like property.
The New testament says "love your neighbor as yourself"...and "Do unto others as you would have them do unto you". While there IS a command to be the husband of one wife..but adds the caveat ..IF you are a Officer of the church..
If sex with my wife makes me feel so good, and if the opportunity arose to have someone else feel my wife's incredible body, making all three or more of us feel just as good.. works for me. I've always felt, she doesn't BELONG to me, I am just incredibly lucky to have her and if sharing is a pleasurable uplifting experience done without deception or fraud..why not? God knows every thought so there's no sense being cagey. God is big time against lying or deception. So as long as you're upfront....He DOES want us to be happy and enjoy the fruits of our labors. best of luck!