Actually they aren't married - The finale was a fantasy episode, it happened in Booth's head.
In his dream they were married and owned the club called "Lab"
So they're not married... yet. We'll wait and see what happens next ;)
There are two schools of thought on that subject Some believe we were seeing a story written by Brennan or the dream Booth was having. I lean toward the dream as he said upon waking up it was so real. Also in the dream he was the good guy and Brennan was the cold fish. She does not see her self in that light. Everyone else does, so she would not write herself as anything but perfect. Either way they are not now and hopefully never will be married unless she learns to be less of a cold fish.