Most Helpful Guy
When the relationship makes you unhappy more than it makes you happy. When you spend more time arguing than working together. Or when you realise that you hardly even talk or do anything together anymore.
Most Helpful Girl
You can tell that it's not working when you're getting tired of it, whether you guys fight or not or are the sweetest of all the couples. It would be over when you think that "it's not worth fighting for anymore", or if "We can't go on like this anymore". And also, you can tell when you start feeling unsure about the relationship and the magic somehow has gone away.