That is a domestic dispute and a legal question that we cannot help with. See your attorney.
Are you sure she filed your return? And the IRS sent the refund? The IRS is taking a lot longer this year due to Covid-19. And how could she get your refund? Your name would be on the check or have to be on the bank account for Direct Deposit or the bank would reject it.
Has the IRS sent it? Did you check the IRS Where's my refund?