Breaking Up & Haircut
A: While it's not exactly fair to make generalizations about the behavior of such a large and diverse group as the female half of the populace, there is some justification to your question.
The responses I got all basically boiled down to the fact that a woman's appearance is something over which she can exercise absolute control. And when a relationship ends, the woman may feel a desire to make a change from what she's been accustomed to in an effort to symbolically start fresh and change the way she presents herself.
In some cases, the way a woman wears her hair may be a reflection of preferences expressed by the boyfriend or husband. (My own mother wore her hair long because my father said that he preferred long hair on a woman.) When the relationship ends, often the reason for wearing a specific hairstyle is removed from the equation, and the woman feels free to please only herself.
There may even be a hint of spite involved sometimes, particularly when the couple still sees one another frequently. (One of the women I spoke with said she cut her shoulder-length hair off to a spiky pixie cut because she knew it would shock her ex-boyfriend, who used to wind his fingers in her hair when he kissed her. She thought of it as her way of letting him know he would never be able to do that again.).
However, in most cases it is simply that at a point of such change and uncertainty in life, a woman often wants to exercise some control. Getting a new look can be empowering and can boost the confidence and help a woman feel better about things in general. This isn't a matter of superficiality, but of self-confidence and self-importance.
©Hairfinder.com
See also:
Reasons to cut your hair short
Why women cut their hair short
Why men prefer long hair for women
Your hair and men