In other words, someone does not have to be exclusively homosexual or heterosexual, but can feel varying degrees of both.
Sexual orientation develops across a person's lifetime-different people realize at different points in their lives that they are heterosexual, bisexual or homosexual." According to Rosario, Schrimshaw, Hunter, Braun (2006), "the development of a lesbian, gay, or bisexual (LGB) sexual identity is a complex and often difficult process.
These include lifelong monogamy, serial monogamy, polyamory, polyfidelity, promiscuity, group sex, and celibacy.
For those with more than one sexual partner, these may, or may not, all be of the same gender.
In 1995, Harvard Shakespeare professor Marjorie Garber made the academic case for bisexuality with her 600 page, Vice Versa: Bisexuality and the Eroticism of Everyday Life in which she argued that most people would be bisexual if not for "repression, religion, repugnance, denial" and "premature specialization." Bisexuality is often misunderstood as a form of adultery or polyamory, and a popular misconception is that bisexuals must always be in relationships with men and women simultaneously.
Rather, individuals attracted to both males and females, like people of any other orientation, may live a variety of sexual lifestyles.
Of youths who had identified only as bisexual at earlier assessments, 60-70% continued to identify as bisexual, while approximately 30-40% assumed a gay/lesbian identity over time.
Authors suggested that "although there were youths who consistently self-identified as bisexual throughout the study, for other youths, a bisexual identity served as a transitional identity to a subsequent gay/lesbian identity." Bisexuals commonly start to identify as bisexuals in their early to mid twenties.  Bisexual women more often have their first heterosexual experience before their first homosexual experience, whereas bisexual men will have their first homosexual experience first. A 2002 survey in the United States by National Center for Health Statistics found that 1.8 percent of men ages 18–44 considered themselves bisexual, 2.3 percent homosexual, and 3.9 percent as "something else".The same study found that 2.8 percent of women ages 18–44 considered themselves bisexual, 1.3 percent homosexual, and 3.8 percent as "something else". The Janus Report on Sexual Behavior, published in 1993, showed that 5 percent of men and 3 percent of women consider themselves bisexual and 4 percent of men and 2 percent of women considered themselves homosexual.The 'Health' section of The New York Times has stated that "1.5 percent of American women identify themselves [as] bisexual. Alfred Kinsey's 1948 work Sexual Behavior in the Human Male found that "46% of the male population had engaged in both heterosexual and homosexual activities, or "reacted to" persons of both sexes, in the course of their adult lives".Individuals who do not experience sexual attraction to either sex are known as asexual.According to Alfred Kinsey's research into human sexuality in the mid-20th century, many humans do not fall exclusively into heterosexual or homosexual classifications but somewhere between. The Kinsey scale measures sexual attraction and behavior on a seven-point scale ranging from 0 (exclusively heterosexual) to 6 (exclusively homosexual).On the other hand, some believe that the majority of people contain aspects of homosexuality and heterosexuality, but that the intensities of these can vary from person to person.