So, DH stepped in it with me just minutes ago.
Note that we have separate personal bank accounts and a joint 'house account' for household expenses ONLY. I keep the information and banking on that one. DH has a lot of debt and is generally not great with money. He used the house account one time early on for a personal purchase, so I removed the debit card for that account to my wallet. He paid that back right away.
Well today the balance on the account checking was ZERO. WTH? Did someone steal our $ or use our card number? NOPE. DH wrote himself a nice check. It would have bounced, but luckily the bank over-drafted it, with a fee. This must be how he paid for some of our recent weekend get-away!
He didn't know the balance b/c he couldn't figure out how to enter the password info (I've given it to him before and he refused to have me access the account for him, on my offer anytime, so he can see the balances). He recently asked me what the balances were and he wouldn't tell me why. Well, now I know. He's been out of checks for his personal checking account and for some reason hasn't ordered them yet - bet he needed $ and gambled on the fact that he could use that account as a personal fund.
I just sent him a lengthly IM letting him know that when he gets back (yes, he's on a personal trip no less) he owes the house account $X immediately to cover what he's borrowed from it. It's not a slush fund but for home expenses and updates and it's my $ he's using as well. He's in debt to me already and he's not doing the same to our needed house money.
I'm going to now remove all joint checks from the office. If he wants to discuss it fine, but you don't do this. Period.