"sexuality not only exists on a continuum, but some people can and do move on that continuum across the lifespan. Sexuality can be fluid, varying across time and situation. Sexual orientation appears to be comprised of many variables–not just sexual behavior. More modern revelations have shown gender to be a continuum and independent of biological sex or gender assigned at birth.
And the truth is, desire/behavior and orientation/identity do not always line up neatly. Some completely straight individuals have unexpectedly found themselves falling in love with and engaging in sexual behavior with those of the same gender. And some people secure in homosexual orientation have unexpectedly become partnered with those of the other gender. How could this happen? What does it mean?
Note that the research does not prove that sexuality is fluid, only that it can be. Studies have shown that sexual fluidity is not uncommon. It is found more frequently in women than men, though it clearly exists in both sexes. This does not necessarily mean that we all experience a degree of fluidity, nor that we are all really bisexual.
It does not mean that coming out as gay or lesbian is reversible or a phase. Nor does it imply that sexual orientations are a choice, or that non-heterosexual people can be guided to embrace heterosexuality. It simply means that while the majority of people experience a stable sexual orientation congruent with their sexual and romantic attractions or behavior, many of us do not.”
- Ellen Schecter, PhD