Behaviorism is a part of your sexual preference, but so is biology. Let me say this right up front to avoid the one statement that pisses me off more than anything -
Homosexuality is not a "disease" or a "mental disorder." After nearly thirty years of researching the homosexual phenomenon - as some people call it - the APA, with a majority of worldly psychological research associations, has declared that homosexuality is neither caused by a foreign element, or a particular deviant behavior. It is not typically considered deviant behavior in the scientific community (although the religious community thinks otherwise), because in many cases, most gay people are not harming themselves or others physically or mentally. There is no solid proof that gay behavior is directly attributed to being exposed to gay behavior.
Now, having gotten that out of the way, we can confidently say that it's a case-by-case basis of how each individual copes with the biological and social urges present. It's a combination of those two factors, as well as personal preference, that drive homosexual tendencies in various persons, and the culture that they grow up in can either lead to unlocking or suppressing these tendencies. In the end, it is the level of acceptance that a person has with the truth about their emotions and physical desires that decides whether they choose to engage in the act of homosexuality with other people.
How's that? Did that put you to sleep?