My spouse is not staying in US and he doesnt acquire any ID from US. How shall I file my tax - Single? married filling separately?

If you are married, you will need to file Married Filing Separately. As your spouse has no identifying numbers (SS or ITIN) you will need to mail your return to the IRS.

If you have a dependent, you could file Head of Household if you otherwise qualify. 

If you are unable to get a Social Security number or ITIN for your spouse, you will need to enter a fake number in the Taxpayer Identification Number (TIN) box and then print out and mail the return. You will need to whiteout the fake number you entered, replacing that with the letters NRA in the TIN box. 

There is an excellent page of information from the IRS here. There is more information about Taxpayer Identification Numbers (like SS and ITIN numbers) here.