Maybe you are the reason why he changed! However, it is not because they have a sweetheart that they will definitely change their image. Some people attract the attention of the opposite sex because they feel that they have no talent for paying attention to image. If you want to know if he has a sweetheart, you can observe his daily life behavior. You can also observe the way he communicates with you. If he is excited or doesn't say much, or jokes to make you happy, then congratulations, you are his sweetheart.