8. Your partner has low self-esteem.
Although a snooper might think that it is the other person who they do not trust, it is actually the opposite. In most cases, when someone looks through their partner’s text messages, emails, DMs, and so on, they’re worried that they are not enough (or, on the contrary, too much), and feel the need to search for validation.
Even in a stable, long-term relationship, these people believe that their partner deserves someone better and, consequently, can be easily attracted to another person.