Yes but there is such thing as a polygamous or open relationship. There are some couples that agree to see other people while also seeing each other. Polygamous/open relationships aren't common but they do exist.
I don't understand cuckold porn. Its just wierd but that people would be fine with their SO cheating on them, it feels so wrong to me, and especially the polyamorous argument that "monogamy is unnatural", I don't feel that way, I don't want to see the love of my life gang banging 7,014 other people
"I do"
"PLEASE HELP MY SON, HE'S-"
"Whoa, dude. I have a girlfriend"
in the lips? Yeah
In the pussy? Threesome
Heart breaks into pieces*
You don't have the duty to love me or anything
it's a thousand dollars
I said it wasn't like you thought