Not sure about the tax aspect of having a joint

account vs giving him cheque or cash. Whichever way you do it, I think you should consider it from an efficiency rather than emotional perspective.

In principle, I agree with Riley in that you might want to calculate the shared expenses and agree on a split (in proportion to income or otherwise).

Don't know what his expectations are - he might have got his own ideas already judging by your comment. If he's flexible, propose something you think reasonable, or otherwise ask for his opinions and decide whether you're happy to go with it. :D