Why you always think your boyfriend is cheating?

I feel the reason we always think our boyfriend is cheating is because were always wondering if he is going to find someone better that us believe me I know what your asking because me and my boyfriend were together for almost 2 years and we just broke up about a week ago and hes with his ex and its very hard for me so I'm trying to move on as well so I'm talking to my ex also. But us girls always have the tendency to think the worst of everything that is why we always assume were going to be hurt but I wish you the best of luck. I hope he's not cheating on you. if this helped and let me know ok.

It is called insecurity, in severe cases, paranoia.