Congratulations! I'm still stuck in "USCIS is actively reviewing your case" but I realized I'm almost definitely getting an RFE from a mistake I made so I'm just twiddling my thumbs until that comes, lol.
If you're not on any financial accounts, I'd try to gather up as much evidence of your relationship (pictures, itineraries from trips you've taken together since moving to the US, etc) and evidence of shared residence (have you gotten any mail? Phone plan in your name?). If he has put you on his health insurance or life insurance, that is good evidence, too. And once you have an SSN, definitely work on getting your name on some bills, opening a joint bank account, and getting on shared credit cards, as you'll continue to need evidence of comingling in the ROC stage!