See, I have the same fear when it comes to my bank accounts, but not when it comes to something like dinner.
My fiance is an economist who is, if anything, extremely careful with spending money (his own or anyone else's). And still, a big concern of mine is when we get married, sharing an account with him -- because my AXH used to burn through his and then get started on mine... So I've already told him that I will have a problem with that, and that we'll just have to find another way to handle the finances than having joint account... so I get that financial boundaries can be very, very important.
It's sad that there are so many freeloaders who don't even have addiction problems. Have they no pride????