Whoa, great question!
In those terms, there is certainly a heterosexual lifestyle. Not all heterosexual people necessarily live this lifestyle, but most do (priests and nuns being an obvious but not exclusive exception, as they are celibate). All priests and nuns are either heterosexual, bi-sexual, or homosexual (pansexual I guess could be included here as well). They choose, however, not to give themselves to any sexuality at all. Do I have anything against homosexual priests who do not allow themselves any sexual contact at all or think that they are evil? Absolutely not. Likewise, I do not think there is anything wrong with harboring homosexual feelings if one tries to live a heterosexual lifestyle.
I don't hate anyone for choosing not to live by my ideals, but I will still evangelize my viewpoint and try to do what I can to help those who are willing to listen (straight or gay).
Once again, I don't hate anyone. I use very absolute, unyielding speech when I outline my beliefs, but that doesn't mean I hate gay people. I just think that allowing them to marry would be condemning them to a horrible fate. I personally have known and heard testimonies given by people who have strong homosexual tendencies that decided they wanted to live a heterosexual lifestyle with a wife and their own children. I believe that if an individual does this with the right motivation, and is open with their partner about their difficulties, they can succeed. Is doing this hard? Certainly it's hard.
There is a perception about asking gays to live a heterosexual lifestyle, and that it is somehow totally radical and different from what others go through, but it really isn't that different at all. Alcoholism runs in my family and if I have a single drink, I won't want to stop until I run out of money or pass out, it's simply how it works. Naturally, as I have that tendency, I love to drink! However, it is for that very reason, that I can never responsibly do so. Many people struggle with sexual addictions, gambling addictions, video game addictions, substance addictions, and other compulsions that they really cannot completely overcome in their lifetime. I'm not condemning anyone for having problems, I have a ton too, but I know that it's my responsibility as a human being to overcome them and set an example for others who wish to.
For some, no explanation I can give will ever be good enough. For people who don't understand the nature of alcoholism, the comparison is probably unacceptable. I hope that makes sense and I welcome more debate*
Edit*
Everyone crams their beliefs down everyone elses throat, in fact, you are doing it now. Relativism and individualism are belief systems, whether you like it or not. Every religion offers a definition of morality, as do most philosophies. Jeremy Bentham comes to mind when talking about collectivism vs individualism.