When he has a girlfriend but still contacts you every day, he is content sharing unique information with you that he isn’t comfortable sharing with his girlfriend.
This is a guy that wants to open up to someone else.
He doesn’t feel that his girlfriend is open to this sort of communication.
His current relationship is lacking.
You are the person that he is the most relaxed with on specific issues.
A guy who texts and calls you once or twice a day, or a handful of times a week, is showing interest.
Keeping this in mind, be clear about what you consider to be “a lot.”
When it is this early in courtship, many guys keep communication at a moderate level.
Gaining further knowledge about who you are as a person matters to him, but he doesn’t want to be too overbearing this early.
You know his interest in you is genuine when he has substantive conversations with you, asking you open-ended questions about yourself and asking you out on regular dates.