In the midst of my W's waywardness a threesome was joked about. She said she was for it, if it was another guy. It was one of those half-joking, half-not-so-much-joking things. I took the opportunity to tell her flat out that I would be opposed to a 3rd party, male or female. Period. A hard boundary for me.
It never came up again.
M(53), W(54),D(19) M-23, T-25 Bomb Drop - Dec.23, 2017 Ring and Piecing since March 2018