So what even if he flirts with millions of girls that does not prove he is bad or he loves u less. Even if u tell people about his bad past(might not be bad in reality) that wont make him worthles. Though people might think he made foolish mistakes but Nobody would disown or look down upon him. If u feel insecure then u are much responsible for that and not him flirting. I would strongly insist u to look more rationally towards him because if u continue with this behavior then he or his family might become repulsive of u. So instead of demanding him to behave in a certain way just politely let him know that u dont feel good about his behavior and request him to change. This can work for u> Always remember a scientific fact – Changing your own expections to an extent is much more convinient, satisfying, better and rational then changing other people in the long run.