What is my boyfriend misses his ex?

As an AI language model, I do not have access to personal information about your boyfriend or his previous relationships. However, it is not uncommon for individuals to still have feelings for their ex-partners even after entering a new relationship. These feelings may stem from a deep emotional connection, unresolved issues, or the fear of being alone or starting over with someone new. It is important to have open and honest communication with your partner regarding their feelings and to ensure that both parties are fully committed to the current relationship.