http://en.wikipedia.org/wiki/Female_sex_tourism
Why would American women need to go abroad to get laid? What kind of women are these? If they aren't hot or decent looking, how are they landing foreign men? Some wikipedia entries are questionable.
These reasons it describes are broad and don't make much sense.
Reasons
Female sex tourism's first and second waves coincided not only with feminism but with Victorian era man shortages that began in England and later occurred in continental Europe and the United States.
Social reasons for women seeking promiscuous and no-strings-attached sex abroad include the dating war, as typified by extreme competition between the sexes in schools, the workplace, while dating, in marriages, and even in contentious divorces. The dating war appears especially to drive sex tourism by Australian and Japanese women, and to a lesser extent, German and Scandinavian female tourists.
The changing theme of pop culture in the wake of the feminist heyday in America and elsewhere cannot be ignored. From the 1970s onward, the emergence of stronger, independent character roles for women in film, music and television doubtlessly influenced the expectations of ordinary women viewers everywhere in the western world.
See also: Hypergamy
The men may do it for the money, or for the sex, or for other unresearched reasons. Women usually give clothes, meals, cash and gifts to their male prostitutes. In some destinations, there are "going rates" for male companionship, ranging from $50 to $200. In other destinations, especially in Southern Europe, Turkey, and the French Caribbean, men do not expect to be compensated.