In 1948, Dr. Alfred Kinsey of the Kinsey Institute, authored a soon-to-be well-known study called "Sexual Behavior in the Human Male."  As part of that study, Kinsey developed the following scale to represent the continuum of human sexuality (with the corresponding definitions presented below):

Scale Definitions (per Kinsey):

0 - Exclusively heterosexual experiences with no homosexual
      experiences
1 - Predominantly heterosexual experiences, only incidentally
      homosexual experiences
2 - Predominantly heterosexual experiences, but more than
      incidentally homosexual experiences
3 - Equally heterosexual and homosexual experiences
4 - Predominantly homosexual experiences, but more than incidentally heterosexual experiences
5 - Predominantly homosexual experiences, only incidentally heterosexual experiences
6 - Exclusively homosexual experiences

• To understand the scale, a "heterosexual" individual would be classified as anyone who fell into "0" or "1" on the Kinsey Scale.

• "But, how could someone be considered "heterosexual" if they have had ANY homosexual experiences?"

The scale builds into it an assumption that some heterosexual individuals may experiment one or even several times with members of the same sex (e.g., childhood experimentation, experimentation as a result of intoxication or drug use, molestation as a child by an adult), but that even having done so, their sexual orientation and attractions remain strongly heterosexual.

• A "bisexual" individual would be classified as anyone who fell into "2", "3" or "4" on the Kinsey Scale.

• A "homosexual" individual would be classified as anyone who fell into "5" or "6" on the Kinsey Scale.

• "But, I was married to my spouse for many years...how could they be "homosexual" if my wife/husband had sex with me all those years?"

The answer isn't simple.  How do people suddenly "discover" that they are gay/lesbian after years of marriage?  Well, for many in that situation, they usually didn't "discover" that fact suddenly.  In many cases, the feelings had been there many years before, but were supressed for a variety of reasons (e.g., society/family pressures, not understanding/dismissing their same-sex attractions, denial of their feelings).  Many of these individuals, by classification on the Kinsey Scale, would fall into a "4" or "5" classification.  They somehow managed to live as heterosexual individuals, but at some point in their lives, their gay/lesbian feelings began to become more prominent, and they most likely felt they had to acknowledge those feelings and deal with them.

• "My loved one has told me that they have yet to have any homosexual experiences with another person of the same-sex.  If that's true, how could they possibly be gay/lesbian?"

An individual who has told you that they are gay or lesbian, but that they have not had sexual experiences with a person of the same sex is most likely not confused (unless they say they aren't sure yet about their sexual orientation).  Just as heterosexual individuals can be virgins and have attractions, both emotional and physical, towards individuals of the opposite sex, so can gay/lesbian individuals be "gay/lesbian virgins" (i.e., people who've had sex with no one, or people who have had sex only with opposite-sex individuals) who have attractions, both emotional and physical, towards individuals of the same sex.  In many cases, a person who is "confused" about their sexual orientation remains in that "confused" state because of their lack of experimentation or experiences with a person of the same sex, and therefore can't be sure about their attractions because they are afraid to act on them and are afraid of society's reaction if they do.  Of course, they could also be confused because they are experiencing attractions to both sexes and aren't sure how to deal with that.