Why is my boyfriend ashamed of me?

I'm sorry to hear that you feel that your boyfriend is ashamed of you. You deserve to be in a relationship with someone that loves you, believes in you and treats you with kindness, decency and respect. He may feel insecure or have other issues that are impacting his view of you and the relationship. These aren't excuses to treat you disrespectfully, if anything it is signalling that he needs help (therapy) to deal with it so that the relationship can be more positive. If not I wish you all the best in finding someone that treats you with the love respect you deserve!