There is nothing stopping a gay person from getting married in Texas as long as they marry a person of the opposite sex. I don't know many gays that would do this but gays are not being denied anything under the laws of Texas. They have the option of a civil contract in Texas too...a bit more difficult than marriage but with all the same rights (at least the ones that apply to gays) as a marriage does.
I think you answered you're own question there Petey. Gay people don't want to marry someone of the opposite sex because they are not attracted to people of the opposite sex. If they were then they wouldn't be gay, would they?
Let's reverse the situation Pete. Let's say that tomorrow a law was passed making heterosexual marriage illegal but legalizing gay marriage. Using your argument everything would still be fair, right? You would still have the right to marry, you'd just have to marry another man. I think that you wouldn't like this "choice" all that much but it would be just as "fair" as gays marrying someone of the opposite sex.
Frankly I don't see what all the fuss is about. I am a heterosexual man and I have no attraction to other men. Some men are attracted to other men and some women are attracted to other women. That's who they are. I may not uderstand the attraction but allowing them to marry doesn't endanger my marriage in any way so why would I care?