It's about society's idea of what it means to be a woman in a relationship. She wanted to be free, like a bird - instead, he wanted her to be a girl.. the housewive, demure, etc. with no urges to do great things... so she proclaims she has to fly - away.
I don't think it's about sex really, though I like your idea of mindless sex slave - it correlates to what some men think women should be.
It's about society's idea of what it means to be a woman in a relationship. She wanted to be free, like a bird - instead, he wanted her to be a girl.. the housewive, demure, etc. with no urges to do great things... so she proclaims she has to fly - away.
I don't think it's about sex really, though I like your idea of mindless sex slave - it correlates to what some men think women should be.