The best way to a man's heart is through his stomach. And the best way to spark a woman's libido and passion is to love her and romance her. So why not do both?
OK – so maybe you can't cook. Here's an Idea… Call her and tell her you have dinner handled tonight. On your way home stop and get her some of her favorite type of food. When you get home, leave it in the car, go in and draw her a bath, throw some bubble soap in it and light a couple of candles. Put on some relaxing music she enjoys and invite her to just relax in the tub while you get dinner ready.
While she's in the tub, set the table and put two candles on it. If you have kids, they can help. If you have a baby, then carry him/her if you have to, this should only take one arm.
Get out a couple of serving plates and some serving forks / spoons. Stick the food on the serving plates and wait. After about 20 minutes, let her know that dinner is ready and ask her to get out of the tub. While she's drying off, heat up the food in the microwave and then place it on the table. Light the candles. Put the lights on low – or if you have no dimmer switch, put a light on in an adjacent room.
If you have kids, have them sit down first. Be a gentleman and pull your wife's chair out for her to be seated. Serve her some food and then serve yourself. If she asks why you did all this, smile and say: "just because." Enjoy your meal together.
After dinner, let her relax while you clean up. She'll appreciate it. Have no expectations and no "hopes" of sex – she won't feel any pressure. This will charge her passion and libido batteries. If you see no results now, you should after doing these kinds of things for a while. Just love her and enjoy the smile on her face. She'll want to be closer and closer to you.