I think it comes down to two things:
One, actually liking the person. I've had great sex with men that I didn't particularly like. It was great, but not for long. I truly enjoy my husband's friendship. He is funny, intelligent, kind, and doting. When all the clothes are on and we're sitting in the cold house in front of the tele, it's so wonderful to just BE. If you can enjoy those quiet moments with the person, the great sex just comes a lot easier.
Two, making it a priority. Sometimes Life can just get too busy. Work, classes, cleaning the home, training the dog, caring for children. If you aren't careful, sex goes by the wayside because you're too tired to do anything. But scheduling time away from everything is really the only way you'll focus on it to do it. It may sound unromantic to schedule sex, but it doesn't have to be just sex. Start off with a quiet dinner away from the kids or the house and turn off the tele. Cuddle and talk, share your day, while you're wearing jammies or nothing at all. You made it a priority when you were first together, why not do it again?
Andi - of the happily married and loved class