Their is a world of difference in a good conversation, an intimate one and an inner monologue. A good conversation for me is where people listen to each other’s views. Like, really listen and not just glaze over what the other person is saying or try to dominate over the conversation. There is no limit on the number of people provided they are willing to discuss rather than bullying their way through.
An intimate tête-à-tête is with people who we trust to listen to what we have to say and not blabber it outside. Generally different type of problems invite different type of confidences to varied trustworthy people. Like, you cannot tell your mom about the new crush on that girl you met in class yesterday. That has to be either a sibling or a close friend. Discussions on life and philosophy and different other questions that trouble us from time to time are generally done with friends.
In contrast to this, a dialogue with self is generally best done when alone or with someone who is comfortable with silences and understands that there is no need to fill the gap with voice every time.