I don't think people are being fair.
OP isn't a deliberately inflammatory homophobe posing a question to be idiotically provocative. She isn't missing the terrible history that lies behind the fight for gay people to have human rights under the law. i would also point out that quite a lot of women struggle to accept the idea of marriage, because in the recent past it legalised rape, and in the not that distant past it deprived women of all rights whatsoever, short of actually being murdered. In her case, the thought of promising love and fidelity forever makes her squirm. The wording makes her squirm. And there IS a more fluid version of lifelong commitment available now, to gay people. Even if the unpleasant side of that is that they are denied full equality under the law, and the right to marry the person they love. I agree that it's something of a privilege to be able to say, well, I just don't want to have to say the marriage service words (and the simple solution would be to allow people to write their own marriage vows, regardless of sexuality) but the very term "marriage" is loaded to some people in a way that makes them very, very uncomfortable.
In my view we won't have full equality until there is no "equal but different", no muddled compromise, but I also think civil partnerships should be retained, for all. I also think it's worth pointing out that surveys a decade ago found that 70% of people thought if you lived together long enough, you had a "common law marriage" and similar rights. An awful lot of women have been screwed over by that mistaken belief, after shying away from a wedding, or drifting into cohabitational families without any clear understanding of the legal risks. Others have found their DP dies, and they are treated as strangers under the law. Most people don't think that hard about the legal consequences of their family arrangements until everything's gone tits up. If a civil partnership option - without the full emotive wording, or the significance of the word "marriage", but with legal consequences - was allowed to straight couples, coupled with a publicity campaign explaining that you have no more rights to support after raising a man's kids for 20 years than a stranger in the street would, maybe a lot less women would be in dire financial straits after childrearing outside marriage.
I should add that I've responded to the gov.t consultation on gay marriage in order to express strong support. I just don't see why a smaller problem should trump a larger one (and when it comes to cohabitants being penniless through lack of a piece of paper, when they'd be in a strong position were they married, I don't think that is a small problem, either, though the OP's reasons may be comparatively trivial).