Jumping Frog

I was told this story some time ago. I'm not sure of the exact words. It went something like this...

When you are in a relationship it is much like a frog in a pot of water. If the relationship becomes unhealthy the heat ever so slowly increases. Over time, the tepid water becomes warmer and warmer. The frog becomes accustomed to the slowly increasing temperature not realizing it is weakening him/her. As time passes, the water boils. The depleted frog cooks and dies. He or she never realized the danger because the increasing heat had became the norm.
The same frog put into a pot of hot water would quickly jump out. The intense heat of the situation would be obvious enough to send him/her on their way!