There are some celebrity couples out there who tried and failed.
But perhaps they ought to try again. This is what Aaron Carter keeps telling Hilary Duff.
And then there are some celebrity couples who have been riding the roller coaster of love and don't seem to know when or how to get off. They just keep going back to one another, time and again.
Some may still have a future, but others should give up before someone truly gets hurt.
We've documented 9 of just such pairings above.
None of these tandems are currently together, but all seem constantly on the verge of rekindling their romance.
But we don't think they should. Not when Justin Bieber keeps one eye on you and another on a Victoria's Secret model, Selena Gomez.
Not when Chris Brown bloodied your face with his fists, Rihanna.
Not when Lamar Odom turned to drugs and to another woman while still married to you, Khloe Kardashian.
Click around the above photo gallery and see if you agree: Should these on-again/off-again couples press the OFF button for good?