I don't know what to think of this issue. I have to agree with what Paul Coleman has highlighted and stated. But before you take Dazmonds advice you need to 'get your own house in order.' Whilst you may have suspicions, you may be using them as an excuse for badly implemented systems.
You don't tell us how you run your 'partnership' or do your days work. But no matter how you work the days taking should 'balance'. (Banking terms.)
Each of us has a float of £50.20. We go our separate ways during the day and at the end of the day the total work payments received, debts collected etc should tally up with the money in the box less the float. If it doesn't then you do a post mortem on the day to find the problem.
I have also been known to lose money, especially if a note ends up in the same pocket as my van keys. I am also hopeless with cash, but I am not dishonest. We are responsible for our own float and daily receipts. If I lose money then it comes out of my daily takings.
I believe that the only way a partner could 'swindle' is to clean a house, pocket the money and put it down as a 'leave it this time.' If this is what he is doing, then an analysis of the number of 'leave it this times' you have a week and he has may be a clue. If he was doing the clean, marking it as completed but not paid and pocketing the money, then you will soon find out when you go back to collect.
The only problem we did encounter was if you had a list of houses with the same price, a payment could be put against the wrong house when entering it on the computer. It becomes embarrassing when you try to collect the debt.
Best decision we ever made was buying George and 2 x Zire31 PalmOne PDA's with pocket George. Tick off the jobs and payments as you go and balance at the end of the day.
If we work together then we just use one PDA and float. We have George set up on each pda with the others work schedule so it works fine just swopping between the 2 as we go.
Spruce