While we chastise straight men who insist they'd only be satisfied with swimsuit models, we tend to accept that a man will not enter into a romantic relationship with a woman he's not attracted to physically. This is in part because of our understanding that it is physically impossible for a man to consummate a relationship with a woman who doesn't to it for him. (One need only point to the children born of marriages in which it later turns out the husband/father is gay to realize why this is ridiculous, but anyway.)
But it's also entitlement. A straight man, if he's going to be with someone at all, deserves to be with a woman he enjoys looking at. As for women? It's not phrased as, women don't deserve men they find good-looking. It's more phrased as, female sexuality doesn't work like that. It's about getting to know a guy, and struggling to overcome whichever natural revulsion to intimacy. (See the "Seinfeld" where Elaine, a woman who sleeps with a healthy number of men, states that the male body is repulsive, and that the woman who appreciate it are perverse.)
But the thing is, women care. This doesn't mean demanding abs, nor becoming repulsed when the aging process does its usual number on one's partner of however many decades. It just means that initially, women, like men, want there to be some physical connection, some reason that this person, of all the people on the planet, is to be more than just a friend. Women should feel entitled to this bare minimum, and yet don't. And yet kind of do. But feel guilty. Leading some to write letters to advice-columnists, such as:
To Emily Yoffe:
I am married to a kind, generous, attractive, wonderful man. The problem? I am not attracted to him. Actually, I am sometimes turned-off by him. I have battled these feelings since before we even got married. I think I married him because he is such a wonderful person, and I thought I would be blowing it if I passed on the opportunity to spend my life with someone who treats me so well. [....]
To Dan Savage:
I am a 25-year-old bi woman in a monogamous relationship with a straight man. We have been living together for about a year, and I suspect he is ready to pop the question any day now. I couldn't be more excited about spending the rest of my life with him. We are emotionally and financially compatible. We want the same things out of life, and he treats me better than anyone I've been with before.
The problem is that I am not physically attracted to him. He is physically a bear—overweight, hairy, and masculine. My physical preference is for twinks—skinny, tall, and hairless boys. When I crawl into bed with him, Dan, I don't really want to jump his bones. I want to snuggle up under a blanket and snooze.
Both of these letters go on, with further explanation as to why this particular case is incredibly unique, as they all are. But the essential in both is that the letter-writer does not believe herself entitled to anything more than being treated well.
Note that in both cases, the woman is not upset that the man has changed physically - there had been a lack of physical attraction from the get-go. Note, too, that the second letter-writer articulates very clearly what it is she prefers, and it sounds kind of... attainable.
If these letters had come from men, one angle that might have come up, either in the letters or the responses, is that it's unfair to your partner to be with them if you don't find them attractive. We assume that a woman's vanity would be just crushed if she learned that a man was with her despite her appearance. But are men so different? "Seinfeld" - the Proust of my generation - says no: when Elaine tells George that a woman he's dating doesn't care about looks, as if this is a good thing for him, George takes this as a negative comment about his looks (which, well, it is) and is less than pleased. So I suppose if women truly cannot demand partners they are attracted to for selfish reasons, they could consider doing so for the sake of the dudes they're with.