Here is why we can’t let “other” people rent space in our heads in a nut shell. They are not other people!
“Other people” don’t live in our heads, they live in their own heads! So, when we argue with “other people” in our heads, we are really arguing with our own selves! Take a minute to let that settle in.
That argument you are having with your lover, boss, co-worker, or friend in your head, has nothing to do with them. Maybe they said something or did something that triggered this argument inside your head, but once they leave the room it's all you. Just like when we dream about other people, those dreams have nothing to do with the person we are dreaming about, those dreams are our psyches way of telling us a story. It just uses images of “those people” to help tell the story. If you have a conversation with someone, outside of yourself, and it triggers an ongoing conversation with “them” inside of yourself, I suggest you find the time to write it out and recognize that the person you need to have this conversation with is yourself and you may find it has nothing to do with the person who started the conversation at all! The most important person you can talk to on any given day is you, why argue with you!