[cocktailpeanuts]

If you really did make up your mind, I suggest you first talk to a lawyer about your potential decision.

Then when all things are clear from the legal side, first try to get this to work (if you still have any hope for this guy). Sit down with him and honestly talk about what you have in mind, and tell him you want to make this work. And make him commit to several things by certain time.

Or you could just tell him you want to split up. (Again, after talking to a lawyer).

You wrote 100% of your code and there was no legally binding document that transfers your ownership so I think it should be fine, but really really I suggest you talk to a lawyer if you are serious about this business. It's worth the money.