A study of college students found that the more time they spent on
Facebook, the more likely they or their squeeze got jealous about the information posted there, leading to more time spent on Facebook and further fueling jealousy.
Facebook could tank your relationship, says the study in
CyberPsychology&Behavior, though obviously Facebook (not to exclude
Twitter, though 140 characters is too short to say anything meaningful) is a catalyst and not the source of the problem.