If you have not lived with your spouse at any time during the last 6 months of the year, have a qualifying person as a dependent and have contributed over one-half the cost to maintain your household you should be able to file as Head of Household.
See this TurboTax support FAQ for HOH when married - https://ttlc.intuit.com/turbotax-support/en-us/help-article/taxation/married-person-claim-head-house...
