Eighty-eight percent of Facebook users said in a survey that they "creep" their exes on the social networking site.
The electronic intrusion causes the targets plenty of distress.
Researchers Anabel Quan-Haase and Veronika Lukacs from the Western University in Canada surveyed more than 100 people and interviewed 10 of them. They found that most of them check their ex's Facebook profile regularly, Toronto Sun reported.
They misinterpret every detail, read into messages thinking there is a hidden meaning, look at photos their ex is tagged in and see whether they have moved on yet.
"For most of the people, it was a real need for them to continue being a part of their ex-partner's life. So after the break-up, instead of trying to move on, they would continually feel pulled back into the relationship through the digital component," Quan-Haase was quoted as saying.
Participants told researchers that break-up behaviours on social media are not taken seriously.
"We realised counsellors and others do not understand how real these interactions can be. Digital media is such an integral part of our identity. For young people, digital is very real," Quan-Haase said.
"It can be helpful to delete an ex and stop creeping them, but many people find this very difficult to do."