aawb:

the intimacy between two people who are in a sexual relationship can be very powerful and special. although there are many ways to have sex, and many different kinds of sexual partners, there are also people in love who are committed and who are building a shared life together as partners. And to get to that point with another person takes a certain kind of vulnerability that is the often then emulated in the bedroom together. So no it should not be surprising that it is within the terms of some (and in fact most) people that that experience is exclusive and personal and private.

It’s absolutely disingenuous to claim that monogamy is solely the byproduct of heteronormative marriage.