A lot of people here suggested you speak with a lawyer and they made it sound like you should do it on your own.
1st, make absolutely certain that who ever you choose as your lawyer is a startup lawyer. Do not contact a family friend who does litigation or someone else that does real estate law. You must hire a startup lawyer who does work for venture firms, angel investors etc.
2nd, From the read, you are worried, but you still think your co-founder is a good guy. If that is the case, you should just send him a link to this post and say: "I asked this question on HN, and it is clear that we may not need to incorporate yet, but I am concerned about protecting the work I have done and will do in the future. Let's start talking to lawyers about everything to get the ball rolling."
By staying positive and just showing him that this is the right thing to do, you are making forward progress. If he balks at hiring a lawyer, you may want to consult one on your own.
1st, make absolutely certain that who ever you choose as your lawyer is a startup lawyer. Do not contact a family friend who does litigation or someone else that does real estate law. You must hire a startup lawyer who does work for venture firms, angel investors etc.
2nd, From the read, you are worried, but you still think your co-founder is a good guy. If that is the case, you should just send him a link to this post and say: "I asked this question on HN, and it is clear that we may not need to incorporate yet, but I am concerned about protecting the work I have done and will do in the future. Let's start talking to lawyers about everything to get the ball rolling."
By staying positive and just showing him that this is the right thing to do, you are making forward progress. If he balks at hiring a lawyer, you may want to consult one on your own.