I once thought I was the only one
When I was dating it would excite me to see my date even dance with another guy, and I had fantasies of sharing them
That caused problems in my first marriage, and we split up after barely 2 years.
Then I met Shelly, my current wife. She was a hottie, we had sex on our first date and about every date after, and it was daily after we married for about six months.
Part of what I liked about her was she dressed to attract, low cut blouses, short skirts with skimpy underwear, and she flirted and teased all of our friends.
One day I suggested going to a nearby nude beach and she was sure up for that, while we were there she was putting on a blatant show, legs open or oiling down her nice boobs, stuff like that.
That night I blurted out that I would find it hot to watch her with another guy, she just grinned and told me she would be up for it.
I already knew she had dozens of lovers before me, but since we were married I was hesitant to talk about my urges.
It only took her two days, she called me at work and told me to be ready for a treat, she was going to do my fantasy that same night.
The guy turned out to be one that worked in the warehouse where she worked as an accountant, and she had slept with him before.
That was amazing to watch, and after he left we went at it also. But I still was thinking I was pretty much alone in my fetish.
Then on the internet, I found some of those cuckold sites, and I realized I sure was not alone. We joined, and now meet various singles several times a month. No jealousy at all, the bigger and better they are, the more we like it.