I never end a friendship (or relationship with a relative) without telling the other person in no uncertain terms why and giving them a chance and a second chance to give me what I am not getting from them, be it respect, good boundaries or whatever.
The problem I have seen is that people don't take me seriously when I tell them "Hey, we have a real problem and this is what it is." I think part of that problem is my quiet off line nature leads some people into believing I am weak and that I won't hold to my word if I say that there will be consequenses for actions.
I find the same thing! I never end a relationship until after I've made that effort to explain what's not working for me, what's hurting me.
Actually, I don't "end" relationships. What happens is, I give people chance after chance, and I share and share, always hoping for the best, and then one day I wake up and see their true colors. Once I've seen that, it's over, because it's become clear that the person is someone whom I would not choose to have in my life. There's no anger or resentment, I'm just not there anymore. I can't be. I have nothing left to give. At that point, I feel very empty inside, and it takes me months to fill myself back up again.
Unfortunately, I don't explain to the other person, which isn't good. At that point, I don't believe they'd understand anyway, so I don't even waste the effort.
(This off-topic to the thinking/feeling thing, but anyway.)