Danielle is a very scarred person. I imagine that her youth must have been pretty awful for her to make the life decisions that she did. These only led to more bad things. Seems like her back was up against the wall with her divorce (i.e. possibly losing the house and way of life, etc.) and she was at the end of her rope. We are seeing the outcome of a desperate woman at a critical stage of life.
Given her turbulent youth followed by an even more turbulent young adulthood, I don't think she ever fully matured.