How do I claim married if my husband is an Italian citizen and lives in Italy ?

To file as married on your return, you must determine if your husband would be listed as a resident or non-resident alien.  To qualify as a resident alien he would need to meet one of the two or the following qualifications:

• "The non-citizen has a "green card," which is an authorization from the federal government to live and work in the United States permanently."
• "The non-citizen was in the United States for at least 31 days of the year, and at least 183 days during the three-year period that includes the current year and the two years immediately before that."

If he classifies as a resident alien you will list him as a resident-align spouse on your return and include his SSN.  If he is not eligible for a SSN, he will need to apply for an Individual Taxpayer Identification number from the IRS and this number would be used in place of a SSN.  See the link below for applying for an ITIN:

How do I apply for an ITIN?

If he does not qualify, he would be considered a nonresident alien.  For tax purposes, you can still treat him as a resident alien.

If you file a Married Filing Joint return, your spouse's worldwide income will need to be included on the return, or you can choose to file a Married Filing Separate return.

For more information on non-citizen spouses, see the link below:

Non-citizen spouse