i deal with this constantly. when it was at it's worst, she would accuse me of looking at other women more than twice a night everytime we were in public. kinda made her an ultimatum and said if she doesn't stop, there's no way we could date. she stopped, but it rears its ugly head once every 5 months or so. two reasons why this could happen:
glitch's post
insecurity/her feeling threatened
most likely glitch's idea