Can someone explain to me why Cynthia Dixon is a lesbian now?

SHOOT: Ok so this lady was married to an English professor. They had two kids. Got divorced and now she wants to marry girlfriend Christine. Can someone please explain this to me? Was she confused when she was with her husband? Was she confused when she had kids. Or was she in a sort of seasonal bisexual phase...okay I'll go for guys...hmmmm...let's try girls. I just think it is very odd to get married in your life to 2 people of the opposite sex. That has got to be very weird for your kids. I think this sort of chronic indecisiveness relating to the sex of one's mate should be discouraged.

clipped from omg.yahoo.com Cynthia Nixon is making it official with her girlfriend of nearly six years, education activist Christine Marinoni. The Sex and the City star, 43, showed off her diamond engagement ring at the Love, Peace and Marriage Equality rally for gay rights in New York City Sunday. The event supported New York governor David Paterson's proposed bill legalizing same-sex marriage. Nixon has said she would wed "if it became legal in New York. "I don't really want to get married to get married pretend. I think we'd like to do it in a real, actual, legal way that the state would recognize." The actress is mom to Samantha, 12, and Charles, 6, from her prior relationship with English professor Danny Mozes.