How do you stop giving your wife your "leftover" energy at the end of the day?

Work gets 100% of me, and by the time I'm home with her, I’m just a ghost on the couch. The kids are grown and mostly doing their own thing, so it’s just me and my wife at home in the evenings. You’d think that would be easier, but honestly, I’ve been coming home like a total zombie. I don't want her getting the leftovers of my energy for the next 20 years.