But, I'm detecting that this is an issue of lack of romance, lack of emotional connection, and lack of day-to-day intimacy.
Make it a point to tell her how much you love her and why, not only how beautiful and sexy she is (but that helps too!). Notice when she does cool things, no matter how big or small and TELL HER. Set up a date -- Don't ask where or what, just set up something great and take her out. Treat her as if you just met her and are trying to woo her. Make sure you LAUGH together -- it is powerful in connecting and elevating passion between two people. Do unexpected, different things that you usually don't do, whatever that may be (draw a bath, bring home her favorite dessert, grab her and dance with her when you have music playing in the house... whatever "works" for who you and she are...)
DON'T back off entirely from initiating -- that'll never work. You MUST keep trying and initiating and showing her that you desire her. But, you MUST have love simmering all day and night to set the stage for ML. You can't just be friendly roommates and then dive in for the kill. Make sense?