In response to georgiagail, schedules make it feel awfully clinical to me, and if there are any lingering feelings of doubt towards intimacy, a scheduled sex day can actually backfire catastrophically. YMMV, of course, and it works really well for some couples!
OP, the best anecdote I've ever heard about men versus women in marriages is this: men need the physical to feel loved, women need love to want the physical. If you can keep the cycle going between you, you're a dynamo of both love and sexuality.
One tip I can give is to simply be affectionate with each other. When he is caressing you, he is trying to show you that affection. Touch him when you pass in the hallway, kiss him (a real one, not a peck) when one of you leaves the house. Hug him when his back is turned to you while he's working on something. If you do have any attraction for him, you must be the one act on it... if he's the one constantly trying to get your attention, it's a very one sided battle that you're both going to lose.
Another tip is to make your home itself inviting to intimacy. You don't have to go crazy with red velvet wallpaper or anything, but keeping a place clear and cozy to spend real face time with each other does wonders for keeping love between you.
If sex is truly important to you, then you must make it part of your life. You can't expect it to just happen, as georgiagail wisely said. Spontaneity tends to fall by the wayside in marriage, in exchange for comfort and solidarity. If I'm reading you right, the biggest part of the problem is that you're just not in the mood, which is extremely common and nothing to be ashamed of... but wouldn't you rather be IN the mood? So instead of closing your eyes and waiting for your brain to decide to want sex, get up, go flirt with your husband, and make it happen yourself!