Another reason a relationship would be hacked is the fact that the hacker was once or is currently friends with a member of the relationship and feels like they are losing attention. Usually, the hacker in this case would remind the victim of "old times" or "good times" before their relationship had started, in a desperate attempt to actually pull the victim from his or her lover.
This is a common issue that must be handled with care. Ignore the stupid, do whats right.
Victim 1: oh ya....that sucks those were good times.
Hacker: then get out. be single. its better..like old times
Relationship Hack in action^
Hacker: hey wanna hang out!. oh yea never mind you're probably with (bf/gf name)
Victim 2: ((oh shit. my friend doesnt like me anymore? screw my 50th anniversary date. it can happen some other time))