Not sure if this is the answer you are looking for, but I think since you are married your wife is the key to make it happen at least that is my experience. My wife and I have had a couple of 3sums with females only, not males yet, but my wife has been the one that has initiated the conversations with other females or actually the other females have find my wife very attractive and before you know it, they are making out and of course she brings me into the mix. We don’t look for it and I don’t ask my wife that we should have a 3sum every time we go out, it just happens on its own and of course alcohol always seems to be the ice breaker. Before we actually got into having 3sums we would talk about it in bed and she’s open minded like I am as well, but like I said my wife is open minded. I don’t know how your wife is. You would have to be the judge of that. Maybe you can show her some videos and see how she would react? My wife and I watch plenty of adult videos and that’s where we have conversations on what we think about that or actually even trying that. Just a thought. Hope it helps. Good luck