A person who needs to put another person down to feel good about themselves is called a bully. Bullies are all insecure. Hence, they need another person they can intimidate to feel strong. Vincent is not a friend, and he is just using you as an accessory to validate his little self. You are worth more than that. And you do not need somebody like him around who constantly makes you feel bad and wanna have to prove yourself as valid. You do not need to prove anything to anyone. You always have a choice to walk away from people who don't make you happy. The sooner you allow yourself to embrace that the happier life you will live.