The theories you have posted are nice, but I think they are not strong enough, if you see it in the evolutionary point of view. Biologically the concept of ‘marriage’ is more favoring women than men. The basic animal instinct is to propagate their genes. For male, more they have sex, the chance of propagating their gene is more, but for women, she is fertile only 3days(even less) a month and even if she is successful in that period, she has to wait for another one year to reproduce again (after child birth etc.) So, naturally man worry about the quantity of partners he can get, but women more about the quality of the partner. If you see the sexual behavior of our ancestors, there were always fight between men to get their mating partner. The male have to prove their strength, to prove that their genes are worth and are the fittest to transmit to the next generation. Then why and when this concept of marriage came into existence?
The theory of “population control” is good, that can be justified biologically. The concept of marriage controls males and hence the population. But in nature always the sex ratio is maintained, so, the population control theory can be justified with an assumption that something terribly went wrong with the sex ratio.
But to have a women as a slave, might have evolved when man started being ‘lazy’ to fight with another male every time, when he wanted to have a mate. But to manage slaves is a big disadvantage for him. Also this is against the psychological evolution of men. Men’s psychology always makes him feel confident, only when he gets success after a fight by proving himself. So the “slave theory” favors only a smaller group of weaker men. So, biologically and psychologically marriage is a big compromise a men make and a big favor for women. Why the entire ‘male dominated’ cultures are favoring marriages? When we relax the cultural constrains (like in the western world) we can see less and less men are opting for marriage. I think there should be a stronger reason for the evolution of marriage. This comment is purely based on my readings and discussion I had with my fellow biologist. Please write if there are any flaws in my comment.
So do post your thoughts on the same.