Discordance may create Revenge

I was thinking about things that happens when friends or couples are on a fight, and when one doesn't want to be agree or give the reason to the other, and how this discordance generates a desire of revenge...

Everybody reacts according to their perception of life. When a relationship got broken, both feel cheated either by the way of this life, or by their couples. There is no agreement between them.

This makes relationships a little frightening... It seems that one of them should swallow the hatred deep inside him, even though that hatred is reminded every time the "forgiven" person arrives...

There is a quote that says "Resist not evil", but there is always a limit...