The Overly Possessive Wife

They seem to be a perfect couple: He loves her endlessly and she loves him to the moon and back. They are compatible in so many ways that it seems everything is in perfect order. Well, everybody can say that they are living in a state of pure marital bliss.

Without warning, this perfectly crafted relationship breaks into tiny pieces. The shards of their breaking relationship is gradually sinking its teeth deep into their skin; making them slowly bleed to death and creating a gaping hole inside their heart that can never be mended by any bandages.

So, what could have caused all this mess? What could have changed a perfect marriage into a muddled battle?
Can they still put the pieces back?