You can both claim home office expenses. You would
have to split the “gross” expense amount between the two spouse’s t2125s. Ex:
Bekka & Tom spent $2000 on electricity for their home. Each put $1000 as
their “business use of home” electricity cost. If they both use 1 room out of a
10 room house then each would get $100 claimed as an expense.
You would each have to claim your own expenses on
your own return, if you have separate businesses. If you share a business, you
can split the expenses based on how you split the business, or by whoever
incurred the expense.