Hi. First of all, are you male? Or female? Females can have wives these days... Why does your wife need a(nother) male in her life?
2nd, your wife is her own person. I am a bit uncomfortable with your use of "we."
Are you aware being poly does not mean having 3way sex? Being poly means loving more than one. So, your wife is falling for a guy... And you want to have 3 way sex with him? Or what? Can your wife pursue a relationship with new guy without your "help," or not? Or do you both insist on "only playing together" as so many poly noobs do?
Love withers under constraint; its very essence is liberty. It is compatible neither with envy, jealousy or fear. It is there most pure, perfect and unlimited when its votaries live in confidence, equality and unreserve. -- Shelley
Mags (poly, F, 61) loving miss pixi (poly, F, 39) since January 2009, living together since 2013
"Master," (mono, 36), miss pixi's Dom for 3 years