I'd try to get something in writing, even a text message from him saying it's all yours.

Watch the facebook movie "the social network". Nobody will mind if your business just drags along. If it becomes successful though even the commit in the repo will cast doubt. And investors or acquirers (if that's your goal) want certainty who owns all parts.

I was in a similar situation once, but we had a contract, a self-written one-pager laying out proposed ownership, who will put in what initial investment (domain name, etc, only a couple of hundred USD) and business goal (creating a limited). In the end business partner didn't deliver project specs, his full-time job commitment caught up, and we abandoned the project. Anyway, creating the one-pager took less than an hour, it's worth it.