I know a local lad who's wife does a day a week with him, at the start she only managed an hour or so before she was too tired to work on...
JM,
It's all about training! You've got to train 'em up properly.
The best thing I've done is go WFP for 'tops only'. Okay WFP 100% is pretty quick, but not as quick as not doing the ground floor at all.
Wor Lass does the ground floor! I just bugger off and crack on with the 1st floor stuff.
For example, when we do terraced houses, such as we did today, I'm often five or six houses ahead of her. It's currently 'mad week', so I prefer to keep my distance from her anyway.
She knocks and collects the cash, or leaves a 'chit', when she's cleaned the ground floor.
It's great. We hardly see each other in some areas.