There is the old wine and dine. Take her out and romance her like you used to. Or simply come home, grab her and kiss her (doesn't work so great if you have kids), but worth a shot. I guess I'm confused as to what you are finding so difficult. As a married lady I even respond to "let's have sex"..."okay" to more elaborate set ups. They all can work. What isn't working for you?

Yeah, if you're married, why are you tip-toeing around this issue? Don't feel embarrassed or awkward about just asking for sex (politely, mind you). But I agree (once again) with Lyz's response. Set up a romantic scenario! Take her out to a fancy dinner and a show. Arrange a summer vacation somewhere and have great vacation sex. Just do something instead of overthinking the whole thing too much.