You can file as Head of Household if you have not lived with your spouse at any time during the last six months of the year, you have paid for over one-half the cost to maintain your home and you have your child as a dependent on your tax return.
See this TurboTax support FAQ for Head of Household when married - https://ttlc.intuit.com/community/married/help/can-a-married-person-claim-head-of-household-filing-s...
