Basically, you split *EVERYTHING* right down the middle when filing MFS, assuming both parties own the rental property.
Be aware that when a married couple files separate returns, they both "automatically" lose a fair number of credits and deductions they would otherwise qualify for if they filed joint. So you'll both lose things like the EIC credit, the $25K rental loss against other ordinary income, any and all education credits and deductions, and quite a bit more will be lost or extremely limited.
Also, if one of you takes the standard deduction then both of you "must" take the standard deduction - even if itemized deductions would be higher for one of you.
If one of you itemizes deductions, then both of you "must" itemize deductions - even if the itemized deductions of one of you is ZERO.
Bottom line is, when you both file separate returns, your joint tax liability is going to be higher than it would be if you filed joint.
