Good question! Me and hubby have discussed this on various occasions. Definitely the real thing is better than the fantasy. The experience of meeting another man, not knowing a lot about him and then having sex with him, has been a massive turn on for both of us. And then this makes the fantasies going forward even more exciting as you build on what you've already done.
As far as being addictive, I definitely think so. It's impossible not to do it again once you've gone with your first guy. Even when I've taken gaps in seeing guys me and hubby have discussed our next meets/guys etc.
But like any addiction it can become a bit risky as you go deeper in it. From going with a couple of guys to begin with, I have done things I wouldn't have dreamed of a few years ago. You want to push your limits and try new things- full photos, strangers, bareback, swallowing, tattoos, fisting, facial, rimming, BDSM, pain etc.even now seeing an ex bf from years ago.
Couples should try moving from fantasy to reality, even if it's just once- but I promise you, it won't be just the once!