I totally understand what you are saying. It can be very tempting to wake your baby but Ive found that this usually backfires and they end up going to bed late anyway or having a bad night of sleep. Of course when I see my 8MO falling asleep in the backseat after dropping my older daughter off at Kindergarten at 8am, and I want her to stay awake for awhile longer hoping she will take a longer nap when we get home, I will stop at the store and purposely get her out and wake her up.
I know its hard to get everything done and there isnt much time for you and your husband. I feel like Im 10 steps behind on all the things I need to get done yet Im running around like crazy busy doing things. It gets A LOT harder with 2 kids. Just do what works for you and if that means waking him up from his nap, then no biggie. As long as hes not too cranky. My baby only takes about 20 minute naps so its really hard to get things done