you can't give each other something you don't have

The key term is mutual, which implies a reciprocal relationship, the way 6 is to 9. 

Although mutually monogamous usually means missionary, as in, a tuxedoed Mr. 

launching the arrow of his (r] between her [M] and [s.] after a long run of near 

misses. Mutually monogamous = only us, 1+1, it's considered a closed system—no 

one can get in or out. And when no one can get in or out we call that a jail cell. 

It's true, this method can prevent disease because you can't give each other something 

you don't have. But a relationship is like trying to put two halves of an orange back 

together: you have to keep holding them there or else they fall apart. Mutually 

monogamous insists a couple can't be split in two for the same reason you can't 

cut a hole in half. Because there's no such thing as half a hole. A hole can only be 

made deeper, like a well, or filled in, like a grave. Because you can't give each other 

something you don't have, sometimes people step outside of their relationships. 

It's a terrible thing to plunge in a well or be buried alive. On the other hand, 

having sex with other people is like passing love notes between bodies. That's how 

HIV slides a letter opener into the slit of a white envelope or syphilis screws 

its way subsurface. In jail, one of the few pleasures is writing and receiving letters. 

You can choose to be mutually monogamous or not (that's on you), but shhh, keep 

it to yourself whatever you do. 

 

[Benjamin Garcia 'Mutual Monogamy', from Thrown in the Throat]