> I've often felt bullied and mistreated by this person, who treats me like a "resource" and bosses me around like a child. > My attempts at discussing/negotiating this with my co-founder only stir hostile, belittling responses from him.

I wonder if there is much "friendship" left now.

However, you should take a break for a few days/weeks so that both parties can cool down, and then try to talk to him again. Hopefully you guys will be able to patch up things and launch the site.