What will I need in order to prove that my spouse and I have been separated for the requisite period?

You will need to have a third party over the age of 18 who can verify the date the separation began, that the spouse on that date had the intent that the separation be permanent, and that the separation has been continuous and uninterrupted since that time. The third party can provide this information by deposition, affidavit, or live testimony before the court. The third party witness should be someone who has visited your residence on multiple occasions since your separation.