A guy who genuinely likes you and is troubled because of his past relationships will pull away for a few days to only a few weeks. After that, he realizes nothing is better without you. So, he returns promising to be better and prove it. But if he pulls away for more than a week, it means he is already seeing someone else. Maybe it's not exclusive yet, but he isn't as serious about this situationship as you. If he pulls away for very long, don’t pursue the relationship because they aren’t seeking anything long-term with you.