Alimony and spousal support for divorces and separations finalized after 2018 are no longer taxable or deductible.
Child support provided or received is not reported on a tax return.
If you are not legally married as of 12/31/2019 then you can only file your 2019 tax return as Single. Unless you have a qualified person as your dependent, provide over one-half the cost to maintain your household and meet the other requirement you can file as Head of Household.
See this TurboTax support FAQ for Head of Household - https://ttlc.intuit.com/community/family/help/do-i-qualify-for-head-of-household/01/25539
