The $5K deduction cap is for state and local taxes (property taxes, state and local income taxes, or sales taxes). Mortgage interest is not included in that $5,000 limit.
Generally, only you can claim the deduction for property owned solely by you. See this IRS FAQ about splitting itemized deductions on a married filing separately return. That IRS guidance includes this:
".....if only one of you is eligible for a deduction for an expense (for example, real estate taxes on a property owned only by the eligible spouse), only the spouse who is eligible for the deduction is allowed to claim it, even if the expense is paid from joint funds."
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
