Most Helpful Guy
Well, that's tough to say. There can be a few reasons, Some of them are :
1. The best time to consider ending a marriage is when your partner has cheated on you.
2. Second best reason would be if your partner has resorted to playing mind games like always trying to make your jealous using the opposite gender, and if your partner does this most of the times, it's an indication that the relationship is not ideal, and that it lacks maturity so that would be another reason to end marriage.
3. When your partner is falling out of love with you and that you believe that you are slowly getting trapped in a loveless marriage.
4. If you have a doubt and if it's confirmed that your partner has fallen in love with someone else, despite being married to you then that would be the best reasons to end marriage.
Of course points #1 and #4 are connected and can go hand in hand if you know what I mean.
That's what I can say.
Most Helpful Girl
When there's nothing left worth fighting for. Or if only one of you is making the effort to make it work... you can't fight alone
Obviously if there's any form of abuse or betrayal involved... those should be a " given"