NO one talks about it, have you ever dealt with bad business partners? What did you do to fix it?

I've not dealt with one. But I've seen how one bad partner can ruin the business and it's very important to act upon it immediately, however hard it is

Yes I have. There are a few strikes you can give them(silently) and express your discomfort each time they cross a line. And ultimately just prefer to ditch them despite multiple warnings. And keep in mind since the beginning if the vibe is off, it's a bad deal.