I founded a company with 3 friends. We'd all worked at the same company previously. Two of us took on more leadership roles in the new venture, two more focus

I founded a company with 3 friends. We'd all worked at the same company previously. Two of us took on more leadership roles in the new venture, two more focused on engineering. Between the four of us, 10 years later, two of the original founders don't really get on anymore, but the rest of us remain friends. From my point of view, the friendships helped us to overcome difficult situations where we disagreed strongly. I found it helpful to be able to trust the others to speak honestly, to advocate strongly, and to work towards our common good. Also, if you're going to be spending all day every day working with someone, liking them helps a lot :-) I suspect there's no good way out when breaking up a partnership as intense as a startup. No matter what the reasons, it's hard on all parties. Making sure the legals are clear up front can only help, of course. I would say "do it": the benefits outweigh the possible costs.