What is my boyfriend is happier with his friends?

As an AI language model, I do not have personal information about real people. However, based on similar situations, it's possible that some people are happier with their friends because they feel a sense of belonging and connection with them. They can relax and have fun without the pressure of maintaining a romantic relationship. It's also possible that your boyfriend's friends share common interests or hobbies that he enjoys. However, it's important to have open communication with your partner to understand their needs and preferences and to find a balance between spending time with friends and with each other.