My Partner is a Flirt

If your partner flirts and she reasons out that this boosts his/her ego knowing that she/he still has that thing that could attract people to him/her. and this makes him/her feel young and happy. Would you really consider that reason or she's/he's only making a reason to flirt and become irresponsible with her/his actions which may lead others to hit on her when she's/he's not even single and she's/he's doing it in front of you. even looking at or checking out other men/women right in front of you which means he/she does' respect you that much and this would make you feel that your not enough for him/her. how will you make him/her to understand how you feel when he/she does that and how will you stop her from doing that? if that is so, will you just leave her/him and find someone else who wouldn't do that to you and who wouldn't make you feel that way? it really means disrespect for me...