I love polygamy dating

I just broke up with my boyfriend because he doesn't support to have a polygamy dating with another one. I'm open minded and prefer to have an open relationship than traditional one. When I brought up to have a threesome dating, he got angry and pissed off. Honestly to say, I don't get it. Don't all men have tinder threesome fantasy? Or is my ex boyfriend just into monogamy? We had a big fight for this and broken up. And then I have dated with some couples for threesome who like swing lifestyle as I do. I can say that I really like it.