Yes the more I think about it the more I think you need a three week cover story. Some kind of thing you are doing that helps the business but requires you to go out to 'the library' etc and maybe requires money for books, travel etc. After all he did say you could do pottery 😁
Because your day to day routine will be different and you will have a different air about you and you'll need a nice ready made explanation for it. He has a business so you could look at courses on maybe marketing, or websites, or social media, or extra accounting, or hmrc latest regs. Then quickly get just enough info online to drop buzzwords and sound boring.
You could also 'pay bills' if you have a VERY trustworthy friend or can set up a second bank account under a BS sole trader name. So you set up SA Online marketing or a SA Services and it has a bank account (easy peasy with your current bank) then you 'buy' services and put it in the accounts as a service with 'invoices'. It's not actually as illegal as it sounds (you are entitled to bill your own company for a service you provide).
I'm surprised you're not currently paying all or some of your salaries with dividends. Also beware directors loans if you have them. If he 'pays his back' and you don't (because you have left) you will be liable for the money you owe. Or will have to give him your shares.
Also if you structure your exit properly you will both save a fortune on tax. It's some kind of directors capital gains relief - I'm assuming marital payouts are taxed? If they aren't it still might make sense to do things like make yourself 'redundant' which is a nice payout that is tax efficient-ish For you. Shame furloughs at an end.
Also why don't you have a business bounce back loan? Free money for a year takes days to get. Up to £49 k easily. Low interest rates after a year. Just apply online through your bank!