I think this stems from my last relationship. Where, with my boyfriend i was conditioned to image every girl as a threat. My ex would always flirt with girls in front of me/text them behind my back, and eventually i found out he cheated/tried to cheat a few times. And in the end, my ex broke up with me by never talking to me again and dating a new girl.
I know my boyfriend is different, but at certain i cannot Control my reactions and thinking. The fear and danger seem so real and strong :/