Monosexism
Monosexism is a term used to refer to beliefs, structures, and actions that promote monosexuality (either exclusive heterosexuality and/or homosexuality) as the only legitimate or right sexual orientation, excluding bisexual or other non-monosexual orientations. The term may be considered analogous to biphobia.
The term is primarily used in discussions of sexual orientation to denote aversion towards all non-monosexual people as a social group or as individuals. It was likely adopted in place of unisexual, which is already used in biology and would produce confusion. It is sometimes considered derogatory by the people to whom it is applied,.
The proportion of people who fit into the category depends on how one uses the word. If the term is used to mean exclusively monosexual in behavior, then according to Alfred Kinsey's studies, 63% of men and 87% of women are what may now be termed "monosexual" as determined by experiences leading to orgasm. Freud thought that no one was born monosexual and that it had to be taught by parents or society though most people appear to believe that monosexuals are in fact the majority and identify as such.
Read more about this topic: Biphobia