peggy, those are fair questions.
Why did I get married? In short, I needed a visa to stay in DH's country and had run out of other options! 
I think you misunderstand me though. I'm not against marriage. I love my DH, I was very happy for us to make a public proclamation of our intention to be together for as long as we stand each other, to celebrate that with family and friends and to have a very fine party! I enjoy the legal protection marriage affords both me and my DH. As a concept, in modern terms, I thoroughly approve of it. In the same way that I approve of people joining the library!
I just don't see it as a source of pride, is all, just a practicality for defining a long-term relationship.
And as for why feminists compromise their belief - while ideals are all very lofty and good, and in an ideal world the legal joining of a man, a women and all their worldly goods wouldn't have a shadow of an oppressive history behind it, we live in the real world. Marriage offers women legal protection.
youngblowfish explained it very well upthread:
"Indeed, penguins.
Which is why I am married. I may be a feminist, but I am not delusional and understand that the strength of my convictions won't be much good when I need legal protection inside a patriarchal set up. I don't feel great about it and I certainly don't see it as a free choice - it was the best option available to me at the time, across a set of options which were all circumscribed by the social implications of my having a womb.
What I would like instead of a traditionally demeaning ritual and the promised land of domestic servitude is proper equal pay, proper legal protection and for motherhood to stop being such an obstacle on the job market. The patriarchy can keep the ring."