Ask HN: Advice for splitting up with cofounder?

I think I need to part with my co-founder. I've not "broken up" with someone like this before though I understand it's common. Any advice?

My story: I'm 8 months into a new B2B SAS business. I invented our product, built a prototype good enough to land a $200k seed investment from people who know my previous work, and then spent 3 months looking for someone technical to join, get founder's shares and a small salary, and be our CTO while I take care of marketing, design, sales, and money as CEO.

I found a guy who came highly recommended from people in my city. We spent 4 months building the product out. I designed it and he built it. I found us two customers and we put things into production in early 2011. We're now making just under $1k/month and stand a good chance of hitting $5-15k/month within 6 months.

My partner has always been kind of hard to work with, but my patience has worn out and I'm done trying to save the relationship.

I am the sole director of the company and own the vast majority of our common stock. He does have some though, and I was naive enough to just grant it to him up front. Our lawyer says its lamentable but there are ways of dealing with it.

I do not have an immediate replacement lined up. Mutual friends of ours have offered to help keep the lights on for a few weeks, but I'm looking hard for someone to formally step in for the short term or long term.

Tips on how to unwind this relationship in the best way possible?