Great question and one I've discussed with other people I've met that enjoy sharing wife or cuckhold and have found that what I loved at the beginning and with her 1st experience, my close buddy getting a divorce that not only was her 1st but became her 2-yr friend w/ benefits fuck buddy, to her other adventures and most recent buddy who we call the Bull (for all th reasons you would call someone a Bull) are different.
At first:
1) loved watching the new clothes arriving at the door that she would try on for me knowing she was dressing sexier, wanting to be desired by my buddy and other men. This included numerous orders from Wicked Weasel and she'd always show me which WW she was wearing out for another man
2) Kissing, groping each other, watching few of my buddies hands on her ass, squeezing as they have their tongues down each others throat
3) Listening to her moans on the other side of the door before I walked in making sure their fun time play time has started. She doesn't like me there the 1st few mins that she calls her how are my clothes coming off warmup. Walking in and seeing my buddies faces between her legs
AS time has evolved:
1) one thing anyone that is thinking about sharing their wive needs to know and come to terms with is you are going to see a very slutty side of your wife that you either haven't seen before, or it's been years since you saw that side or rarely comes out. Once they understand the line has been crossed and you won't get mad at them their inner slut is out and on center stage. Learned it's because they want to impress their new lover, be wanted again and again so your wife is going to pull out all of her sexual tricks and probably agree to do things that are outside of your normal love making
2) Love hearing the naughty things she says to her Bulls "Please cum all over me" "Need to feel your cum in me" "Spank me" and my fav 1-time let me know when you're going to cum because I don't want to miss a drop (and my wife has never been one that likes to swallow).
Things that still get the jealous emotions running hard but always overcome with how turned on you are (vicious battle in the brain)
1) Seeing wive on her knees being completely submissive to the Bull as he fucks her mouth with power and aggression holding a hand on back of her hand. Yes it's hot but still makes me jealous
2) Few times she ask to go to their house solo that I granted permission. I pace nervously entire time she's gone wanting to know what is happenning, has her inner slut come out and she's giving him everything he wants in more, is she going to have a bangover (pussy took a beating and on DL for a week).
I know thats a lot to write but great question and find my answer differs on when, who, and experience but there is nothing comparable to watching your wives inner slut come out, not want you and want to be dominated by a Bull that you know and give anything and everything they want