Well my wife's boyfriend and I are friends. We have our own conversations, our own inside jokes and interests that she does not share.
The first time we met was very brief, he picked TP up from our house. Mr A came in and said hello, shook hands and TP made her way outside to her car (she was FAR more nervous than either Mr A or I) To my surprise Mr A and I close the door as a joke to play on TP's nerves. From then on out he started coming around for dinner which eventually grew into a weekly hang out for dinner at our house; we've gone to movies with TP and out for dinner... We've not been able to do that since he moved away for work and it's honestly something I've missed.
I had to get over a lot of jealousy and insecurity, but that was with guidelines that allow me to be comfortable with TP and Mr A cuddling on the couch with me there or cuddling with Mr A there. I would say that just meeting the person is not enough, you need to get to know them...It made all the difference to alleviate anxiety.
Polyamory is wrong! It's Multiamory or Polyphilia. Mixing Greek and Latin roots? That's wrong.