I'm the married mother of none, but I find myself in the "not a whole lot of time" boat as well. I work 40 hours a week, with a 45 minute commute at either end of those 40 hours. One of my treatment goals is make some of my scheduled activities also about spending time with him.
My husband works the third shift, so he doesn't get up until I've been home from work about two hours, and I'm gone in the morning before he gets home. That leaves us about 3 hours on Friday night, 3 hours on Saturday and Sunday mornings and 3 hours on Saturday and Sunday nights to actually do something pleasurable together.
As silly or obvious as it may seem, but sometimes we have sex during our time together. Sometimes we go out for breakfast together. With being up so early on Saturday mornings, we go to the Farmer's Market that is not far from our house and stock up on local produce. (This also helps my goal of eating better, lotsa fresh fruit and veggies!) We both got bicycles, so we try to go for an hour long ride on one of our mornings together.
My friend who has two kids makes a girls' night out a priority once every month, where the guys/grandparents are enlisted to watch the kids, and they go and do something... movie, play, concert, drinks at a lounge, just something "grownup" to do. Maybe that's something to consider?