Hi! I also had the same issue with our co-op in Stardew Valley Mobile (Android). Since it’s still experimental, we think it’s a bug i.e. we chose the separate income in the first setting when creating the shared farm.
To separate your income, go to Mayor Lewis’ house. Top left where the Lost & Found bin is. On the left side of the marriage logbook, inbetween the ticket machine, click on that book to separate your farm income in Stardew.
It has to be confirmed by everyone in the farm and if you have existing money from the previous shared income, the game will automatically have it equally separated for each player the next day. I don’t know if this has the same mechanics in the PC version though, but it makes sense if it did.
(I discovered this by accident when I was supposed to click the machine and oh boy did me and my sister rejoice because we hate sharing money. Lol.)
Hope this helps. Happy playing! x
