Gamophobia

Gamophobia (prounced 'ga-me-PHO-bia', from the Greek 'gamo' meaning 'marriage') is the fear of getting married, being in a relationship, or commitment. The opposite of 'gamophobia' is 'anuptaphobia'-it is the fear of not being in a relationship (to be single or alone). A person who has gamophobia may like or love a person, but when he or she finds out about that person liking them back and attempting to be together, there is a possibility that their would change to hate.
Rather than a phobia, such behavior is linked to a number of personality disorders and neuroses. The majority of phobias are socially created, and are not found in any DSM Psychology manual. The inability to allow oneself to be vulnerable and show their 'bad parts' has a personality disorder. When the individual displays reaction formation (love to hate) this is a neurotic defense mechanism. This can also be known as commitment phobia.