Perhaps you should refer to the relevant page of the Polizia di Stato. Among other things, it says:
EC Long-Term Residence Permit (carta di soggiorno) for foreign family members of EU citizens
For stays longer than 3 months family members of EU citizens who are not EU nationals can directly apply for the EC Long-Term Residence Permit (carta di soggiorno) for family members of EU citizens at the local Questura or through the Post Office (using the application kit with a yellow stripe). Designated municipal offices and other authorized offices (Patronati) are available to help applicants fill out the application forms, which must then be sent through the Post Office.
The following documents must be attached to the application:
- photocopy of passport or other current and valid equivalent document, with visa, if required;
- certificate issued by the authority in charge in the country of origin or provenance proving family relationship and, if required, proof that the applicant is a dependant or a member of the household of the EU citizen or that serious health grounds strictly require the personal care of the family member by the EU citizen having autonomous right of residence;
- EU citizen's receipt of application for registration with the Anagrafe;
- 4 passport size photos;
- if the request is submitted by the EU citizen's unmarried partner, proof of the existence of a durable relationship with the Union citizen.
From the following, it can be concluded that a special visa is not necessary to enter Italy for this purpose:
- ...can directly apply...
- ...with visa, if required;...
Under European law, Italy is not required to extend the same rights to the family of Italian citizens as it must extend to the family of other EU citizens. However, it has chosen to do so.
Before you go to Italy, you should get an apostille for your marriage certificate. The office issuing the certificate should know how to do that. For example, if you get married in New York City, you can start at https://www.dos.ny.gov/licensing/apostille.html, but they have a piece of paper describing the process that one can pick up with the certificate.
It may also be smoother if you register your marriage at the consulate before you go, but I doubt it is necessary, especially if he lives in Italy. Still, it is better to be safe than to be sorry.