Sometimes these Visa issues can be a real pain simply because there's no option for Family Members of EU citizens.
Here's the Schenghen Visa Form for Italy
As I mentioned before please notice the questions marked with '*' and the appropriate notes.
The fields marked with * shall not be filled in by family members of EU, EEA or CH citizens (spouse, child or dependent ascendant) while exercising their right to free movement.
Family members of EU citizens shall present documents to prove this relationship and fill in fields no 34 and 35.
I cannot find any requirement for notarised documents, but I do know that many Embassy's outsource this visa work.
I'm also aware that some Embassy's try to force you to pay for the Schenghen Visa. This is not correct and goes against the EU right to free movement of EU members and Family members.
Why not send a simple e-mail to the Italian Embassy asking them about your concerns and asking how they can help you with a Schenghen Visa in accordance with The Schengen Visa Handbook, as you are a Family Member of an EU Citizen exercising their right to free movement.
You should mention that you are expecting this to be issued Free of charge and within the shortest time possible.
Also ask them the specific documents you need to supply with the application form according to EU law to allow the visa to be issued
Nothing to lose by doing that, and I'm confident you'll receive a polite and helpful answer.
Others have done this with positive outcomes.
Confirmation from the Embassy itself is always a good route