Yes, I had a EA for a while many years ago during a relationship, and where an emotional connection existed you do miss an affair partner, for me it lasted about 5 years. Like you would miss a friend who suddenly disappeared from your life, and at certain moments you’ll think of them and wonder how they are doing and wish you could get in touch to ask.
But that is not the only emotion, there’s also regret and despair and shame and angst. And still the factors to address that led to you getting into the mess in the first place.
I learned a lot from crossing that line into an EA - it hurt my AP, it hurt my then DP, and it hurt me.
Now, decades on, I still think occasionally of AP but now it’s almost entirely with overwhelming feelings of shame that I ever allowed feelings to develop. And I remind myself, it wasn’t a real relationship - it existed in a bubble outside real life - you can feel a bit wistful about the might-have-beens, and you have to remind yourself that those day-dreams are fantasy.
I have never cultivated friendships with men since that day, as I consider it too risky. So I guess overall I miss the company of men, because I’ve become very insular.