Yeah, sucks big time when IT encrouches on your formerly bonding time. Maybe you need to make a pact that every time he (or you) gets off of stage, the protocol is to immediatly head back to the partner and give them a big hug or kiss. Anyone who approaches can be told, thank you, but I'm heading over to my W for a kiss right now!
A little sidebar, my FWH told me that at the end of the night, some strange woman sent over a drink to his friend T, and then came up to introduce herself. T thanked her for the drink, she indicated that she wanted to "get closer" to him, and he said sorry no, I'm married. At which point she told him she didn't care. They left the bar to get away from her.
I asked him why T didn't tell her to leave him alone. FWH said that he thought that T was just "trying to be polite." I looked him dead in the eye and said "You do not have to be polite to a woman trying to fuck a married man. You need to tell them to get the hell away from you. T shouldn't have even accepted the drink he should have sent it back. And that's what I expect from you, should you find yourself in that situation." And IMHO, that IS the only acceptable response. It is never rude to proctect your married life.