I am sure that most people have such partners for imaginary conversations, and this includes myself. Even perfectly real persons, alive and really my friends, can function thus in their absence. They may even answer more sagely in my imagination than when I eventually call them on the mobile phone - cursed be it!

My deceased mother addresses me in my dreams, not always pleasantly.

Characters from religious tradition, fiction, poetry, songs etc. frequently turn up in people's imagination, in various degrees of realism. Many (though not I) converse with God, Jesus, the Virgin, Muhammad etc. asking them for advice, even if they do not believe that these actually work miracles upon request.

I know a successful gentleman, perfectly anchored in reality, who told me his secret: since his childhood, he often asks himself (though not the character) what The Valiant Little Tailor would do.

The point is: now act in real life, in genuine interaction with alive people!