Why is it that when these jealousy topics come up i always see the age old defence that it is a males instinct to gawk at other women, and no one takes the time to actually research a females instinctive nature.
Your girlfriend is not abnormal, or weird. Atleast she is trying to communicate with you, instead of turning violent. Female /Female competition has always been. Jealousy is an emotion that is triggered to survive. I'm sorry, but you will find more females that are jealous than not.
Yes your girlfriend may have self esteem issues....are they imaginary or real? Is she overweight? Do you put unrealistic expectations on her? Do you seek sexual stimulation outside the relationship? Do you think you might be making her feel like a walking vagina hole to use when you have gone elsewhere to get turned on?
One motive for violence between women is competition. A woman's reliance on a man for resources ignites the competition between other women. The more a woman needs a man, the more injury that will be inflicted. Research indicates this point when two kinds of societies were compared: matrilocal and patriarchal. In a matrilocal society women controlled the land and were responsible for the resources of the family. There was little aggression between these women because they did not rely on the men to survive. In a patriarchal society though, the men were the breadwinners and supported the females for their survival. The poorer the women the more these girls fought other women off because they needed the economic support of the men. The reason for competition appears to be because the number of men that are actually good providers is far and few between and the number of needy women is great. If a man possesses resources, then he is attractive to women, especially if those resources are greatly needed for themselves. If any female tries to enter the picture of an already claimed territory (a man) than these new girls will be the targets of violence. Men like new bait, so will automatically be attracted to a new girl therefore taking attention and / or resources away from the existing girls causing tension and hatred towards the new girl. This competitive nature among women has been found to exist cross-culturally emphasizing that mate selection and ample resources are key to female aggression.
A Mind of Her Own: The Evolutionary Psychology of Women (pp.169-207).
http://www.drmillslmu.com/Evolpsyc/spr2004/campbell-competition.htm
So i suggest that if you want her to not need you, then encourage her to be better than you. Then she would not care if you stayed or split....