People are insecure about others having ex SO and such because depending on how many ex's they've had its considered a red flag and its also the thought of always having to compete with their ex's......like think about it, if your with your SO and they had a ex or ex's, you don't know if in the back of their head as in subconscious they are comparing you or that moment with their ex's as in they did a better job than you....this typically happens if you have never been in a relationship before and your SO has....