I agree with AngelvMaynard, sexting is a good way to spice things up. Also maybe get some massage oil, and have big kid time and go on a very flirty date, or even just dinner and a movie. I know that can be hard with younger children, but that is were grandparent time comes in, or aunts and uncles if that is a possibility of you guys.
Another idea is maybe inviting in some rope, or cuffs, or even just a feather tickler. The sensations that the feathers make is sometimes just the right thing to make the sex amazing for the night.
I hope this helps babe