should I file as single if I'm married to a non-US citizen who lives abroad?

No. You have to file married jointly, married separately or if qualified, as Head of Household. 

In general, if you're a U.S. citizen or resident alien married to a nonresident alien, your default federal tax filing status is Married Filing Separately. However, you have other options if you qualify:

1. Married Filing Separately: This is the default option if your spouse is a nonresident alien. 
2. Married Filing Jointly: You can choose to treat your nonresident spouse as a U.S. resident for tax purposes. This means both of you will report your worldwide income.
3. Head of Household: If you qualify, you might be able to use this status. You must pay more than half the cost of maintaining a household for certain dependents or relatives other than your nonresident spouse. Details can be found on the IRS page for Head of Household
4. Since you are married single is not generally an option

Choosing to file jointly doesn't change your spouse's U.S. immigration status. If you made this choice in a current or prior year and do not change it, it will continue. Filing jointly may entitle you to additional exemptions and higher deductions.

For more information, please see Publication 519, U.S. Tax Guide for Alien

thank you for the quick reply, 

here's the issue, she lives abroad, never came to US and doesn't have SS#.

That section need me to add her SS#, she won't have one until end of this year when she finally get her visa

You will have to file by mail - you won't be able to e-file.   You can ignore the error as you will be filing by mail.  See full instructions in this TurboTax FAQ.

1. When you get to the “Let’s get ready to e-file” screen, select File by Mail.
2. TurboTax will continue to give you an error regarding the missing Social Security Number or ITIN for your spouse.  Proceed to print with the error but write Nonresident Alien (or the abbreviation “NRA”) in the space for your spouse’s Social Security number before mailing your return.
3. Mail the return to the address on the instruction sheet that prints with your return.