I feel your pain. Been there. I don't know all the details, but if you can't confront him with performance issues, it's not a partnership at all. Buying out a non-performing partner is a waste. You might as well start from scratch in that case.

With other founder, I have advised the following steps:

1. Sit down and be honest and ask them how they suggest you resolve it - you share your side and then collaborate on a plan
2. Hope for the best, plan for the worst: Basically ask him what he suggested if things don't go well and they can't agree - be upfront with the fact that the situation is not going to work and you would rather be friends than business partners
3. Write a letter of what you want to achieve and the grievances you have (get it into your minute books as a legal record)
4. Agree to create an operating/partnership agreement (you should already have one but it might need to be changed)
5. If you two cannot agree, you have already discussed getting him out - then it becomes a negotiation that both of you agree to
6. We can help with negotiation options. There are creative ways.

Hope this helps. I empathize with you. Let us know.