Another cause of occurrence of fear of sex may be parting with emotionally close partner. Not all the girls, and not all men, love the constant variety. After the termination of the relationship so hard for people to regroup, causing panic before sex with a new lover or mistress.
Third place in the ranking took the fears associated with the consequences of sex as unwanted pregnancies or sexually transmitted diseases. Even reliable contraception will not help in this situation. Condoms can break, pills do not give an absolute guarantee, - all these thoughts can cause bouts of fear of sexual intercourse.
Individual factor influencing the perception of sexual side of life, is overpriced or too low self-esteem, which can play a cruel joke with her lover. Do not idealize the partner, as a real person is very different from the picture in my head invented.
Think of sex as part of a relationship between a man and a woman. Do not place any limits, as well as attempt to fight all the fears that sometimes occur.