In the beginning of any relationship, the sex is new, it's constant. You're interested in playing around with the other person. Learning their desires, likes and dislikes. As time progresses and more serious conversation ensues, you may forget to re-visit that physical attraction that you had in the beginning. Your sex life may dwindle from 2-3 weeks to once a week or even scarier, once a month. Men are visual beings and in order to remind him of why he was infatuated with you when you guys first met, you have to give him something to look at.
Do your make up in your underwear. There's nothing more visually appealing than seeing bare beauty. The curve in your spine, to the arch in your foot. Be bare and beautiful.
Throw out any big t-shirts. When you're home, the only t-shirt you should lounge in is something cute in which your cheeks will definitely fall out of like the ones shown below.
Lounging rompers are your best friend! If you haven't seen them, they're the only things you should be cooking in. They're cute and sensual and is great way to get all eyes on you while the football game is on.
Be secretive on date night. Put something surprisingly sexy under your cute outfit. When you guys get home you get undressed it's a more than pleasant surprise.
Do your hair! I can't stress this over and over. It is so easy to put a side part and braid your hair into a bun. You should have the best hair styles at home for the person who matters the most to see it.
Of course just simply being sexy won't keep him. You need to nurture his brain as well. However, the confidence you gain from being wanted and looking sexy will give you the mental capacity to worry about other things such as your goals!