I use this story as an example for my clients so often in my work and I thought I would do a video about it. This is the allegory of the frog and the scorpion.
One day a frog was sitting next to the river sunbathing. Along came a scorpion and he said to the frog "Mr. Frog would you be so kind as to give me a lift across the river to the other side as I really need to get over there?" Mr. Frog replied, "but why would I do that? Surely you would sting me and then I would drown?" Mr. Scorpion replied, "But if I did that then that would mean that I myself would drown and I don't want to die." So Mr. Frog said, "Ok that makes sense, climb aboard."
Soon they were halfway across the river. In the deepest part of the river. Suddenly the scorpion stings the frog. And as they were both about to drown the frog said to the scorpion "But why would you do that? Now we are both going to die?" and the scorpion replied, "I can't help it, it's my nature!".
There are many morals to this story and I know you can figure them out. If you have someone in your life that continues to hurt you, and you allow it to continue, then it just might be time to let them go.