Can my home co-owner still file standard if I Itemize

[pwigdzinski]

My partner (not married) and I both own a home, both are on the mortgage but my social is on all the tax paperwork. I also pay all of the mortgage from my personal account which covers the interest and property taxes. If I Itemize and claim all of that for deduction, can my co-owner still file standard deduction?

[VolvoGirl]

Yes since you are not married and will be filing as Single or Head of Household if you qualify.  

[Hal_Al]

Yes.

You pretty much have a choice. One can claim it all or you can split it. It's usually best if only one claims it, allowing the other to use the standard deduction.

You have to meet the rules, which are:

1. You are legally obligated to pay it
2. You actually pay it. Paying from a joint account where you made sufficient deposits to cover the payments will usually meet this standard. However, paying from your own account would be a stronger audit defense. 

[DoninGA]

Since you are not legally married how you file your tax return has no bearing on how your partner files their tax return.