Hi Dr. Laura!
My husband is easy. He's pretty much in the mood all the time. Whenever, wherever... we have sex at least once a day, sometimes two or three (and we're in our 40's). But because women are different, I found that it's good to always stay "prepared"... One way is, I NEVER go to bed with clothes on. The second is that I have a few things I rotate inside of my head about my husband throughout the day. Things I love about him, things that attracted me to him in the first place. I focus fully on one or two things and before I know it, I'm ready to go. And yes, even with a headache.
My mother taught me to never say no to my husband, but I realize that there is a difference between just being a willing participant and being right there in the moment with him. It's my very favorite part of the life we share, and I think it's his, too.