Social punishment isnt inherent to the social relation we call monogamy, thats social norms, a connected but different thing. We can alle agree social norms often disparage people, but again different conversation.

And its not ‘a fact’ that people in monogamous relations have consent over the other persons body, only their own. If the other person doesnt want to do monogamy, they are free to pursue that type of relation on their own. Thats their choice, as it is the monogamous persons choice to not stay in a relationship with he partner that doesnt want a monogamous relationship. Insisting they have to be together, irregardles of the wishes of the other person, sounds unproductive and unhealthy to me.

“We treat” i dont. I recognize societal norms propogate one type of relationship, but that is once again a different conversation than the supposed ethicales of a social dynamic. The dynamic an sich is different from the norms around it.

Dont let your grievences with the system become judgements of the people caught within.