The idea that marriage is a form of prostitution only makes sense if you're thinking of the wife being kept by her husband, relying on him for money and having to provide sex on tap in return.
Now I'm not saying marriages like that no longer exist, but they become rarer all the time. Marital rape became illegal in 1992.
When I got married we talked a lot about how we wanted our relationship to be. We examined our experiences and decided to ditch things that had been unhelpful a in our families of origin. We decided that being married meant we only had to work by our own rules - our relationship was noone else's business.
I had a career, he had a job (which he didn't enjoy). As soon as we could afford it he became a house husband. He was much better at that kind of thing than I am. I would never have got my business off the ground without his constant encouragement.
A marriage can be any shape the two of you choose. It's just a formalized committed relationship. I'm assuming that lesbian marriages escape the accusation of prostitution, or is it all marriages?
This is really tiresome. Telling women that marriage is prostitution is offensive and - more importantly - it's not true.
It's always seemed to me that as most women are het then we have a lot of power if we only give our love to men who take the trouble to empathize with us, men who are worth our time. My marriage was based on the importance of truthfulness and shared values.