How to breakup with a negligent friend/business partner without destroying our friendship?

My partner and I were friends for awhile before we decided to put up a business together. We were pretty aligned throughout the first few years until he started becoming negligent, passive, and somewhat lazy. To keep responsibilities equal, tasks were still divided but he would end up forgetting his end of the job and in turn, did it badly (forgetting to fulfil orders until I would ask about it, no initiative to strategize or bring up business ideas, not reading emails, etc.). It felt like I had to micromanage, or had an employee I had to supervise and instruct, instead of having a partner.

I am aware of his activities and know he has time to work but just doesn’t, which is so frustrating. I have confronted him before, but now, several months later, things are back to normal and I am really fed up. I’ve told him I am leaving the business (it’s not making enough money and we’ve discussed possibly ending the business before) and he can just buy me out if he would like to continue (which I’m pretty sure he will be unable to do). Should I just let things die quietly and without closure, or confront him again and be completely honest with my feelings?