Quote: During this time, one or another of the kids will often need to be picked up from work, and she always does this, despite my repeated offers to perform this task.
How about if you don't "offer," but you just get up and DO it. Say to her as you walk out the door, "you have a little nap, and I'll wake you when I get back." Or GO WITH HER. Do anything to break the pattern. I know it's not this easy when you're dealing with a resistant partner-- believe me, I know.
NOP's point is a good one: this isn't about physical sex per se, it's about connecting, enjoying being together.