Uh... I am a woman and I love sex and inniciate it all the time, probably even more than my boyfriend does. And I know many many women that do.
There are lots of women that come to this forum and have significant others that act like they don't like sex or don't inniciate.
Its not a man/woman thing. Its a person to person thing. If you are with someone that isn't inniciating it could be very possibly that they are shy, or that they are not enjoying the sex they are having, it could be any number of reasons.