Oh wow I am loving the hate here.
The unhappy one in the relationship - the one who is doing the cheating - is somehow always the monster, right?. No blame ever on the one being cheated on, right?
Adult relationships are never so cut and dry as to be black and white. There usually is a hell of a lot of gray in there that can more than justify cheating.
Yes. The other person can be blamed for unhappiness in the relationship, but no one is ever forced to cheat.