"With so much of our lives online these days, from social media usage to video streaming and online banking, sharing a password means placing a lot of trust in another person," Skyler Acevedo, a Comparitech spokesperson, told the New York Post.
"At the same time, it's important to keep in mind that a misused password can have long-lasting effects and result in more than just relationship issues."
However, experts warn about the risk of taking a partner's online transparency for granted and even misusing trust.
More than half of survey participants admitted they've gone through their partner's messages without their partner's consent. About 16 per cent of them ended up catching their significant others cheating on social media.
A total of 12 per cent of survey respondents said they'd broken up because of that.