As long as both of you are on the title and on the mortgage, you can allocate the property tax and mortgage interest in whatever manner you wish,
Both of you, however, will have to elect the same method of claiming deductions - standard deduction or itemized deductions.
That means if one party itemizes to benefit from a higher percentage of mortgage interest and property tax, the other person will also have to itemize. Unless there are other, significant itemizable deductions, that party will lose the benefit of the standard deduction.
"Married, Filing Separately" is generally not the best approach for reducing your combined tax liability.
See Is it better for a married couple to file jointly or separately? for additional information on this subject.
