Mrrzy,

Marriage as a contract seems to be, frankly, a holdover from the days when women were property. Why else would there be a contract

I think the "contract" part came from the property issues. In the good old days, marriage was often a financial transaction (especially among the rich and powerful). Marriages by us commoners was much less complicated and usually less formal. Until the Church got involved. At one point (pre 1000 AD CE), marriage could be purely financial, involving (anecdotally anyway) marrying a tree so property could be inherited. Not to diminish the "woman as property" aspect but I think developed more fully a little later.

Regards

John