I think the key to being sexy to your partner rests both in showing an interest (a turned on woman is a swxy one I in the eyes of most straight men) and confidence. It sounds like you lack the confidence so you can find it or fake it.

I personally found it through belly dancing, although if you're looking to turn him on specifically (it was a self-esteem boost for me to learn to dance) you could try taking a class on pole, chair, or burlesque dancing. They can give you confidence and teach you moves.

You could also play out his fantasies if you know of any. My husband always liked the school girl look so I bought a costume, put my hair in pigtails and jumped him. He did laugh when he saw it, but that was out of shock (I knew he'd do it), not because I wasn't turning him on.

I will also give him shuttles cues throughout the day, look at him with flirty eyes, kiss him out of the blue, go for a hug, but then let your hands wander down to his *****, lingerie. whatever you do, try to read his responses to see what is working for him

Or you could just say "yes" as it doesn't take much to turn moest men on