I think I can finally say, that I understand it: it is OKAY that I won't have him in my life anymore. I feel okay with it..? Although, I'm a bit scared that it's just temporary, I hope that my soul found the right way to let go of my past.

If someone has ranted to you in a non-constructive way about other people, it is probably safe to assume, that if you step out of their line, that they will talk about you like that to someone else. It is just how most people are. If you are aware of it and they are not talking to you about the issue, that is their problem, not yours. If it does bother you, then dump them.