Okay, I may well get flamed here.
First off, I'm a man, married to a woman. We've been together ages (in our thirties) with a small child.
Basically, my wife has very little interest for sex. She's admitted that to me, and that she has for a while, and basically she only has sex to please me.
She does enjoy it when we have it, and more or less just needs to "get into it", but doesn't have that initial feeling very often of "you know, I quite fancy some sex right now" (though she does get it occasionally). She does say she is attracted to me but, as I say, doesn't get that particular initial feeling.
Part of me has now rationalised this as "well, if she enjoys it and is happy with it, as well as happy with it making me happy, then there's no real problem". That's the part my wife subscribes to, I think.
But then there is another part (and I don't have a lot of self-confidence) which says she's only doing it out of pity, that if she's like this then she should just bugger off and find someone she likes doing.
As I say, not a lot of self-confidence.
She does also have some confidence issues, which I'd like to help work out. Unfortunately, as I'd imagine a lot of men, I can also get a bit miserable (I'd term it more as being silent) if I feel neglected for a few weeks. I don't start fights or anything, but I term it more as feeling as if I'm walking on eggshells.
Other aspects of our relationship are fine - we both pitch in around the house, help each other out and so on. I have no real problem with the frequency of sex, which is about 2/3 times a month (she says it would be more like a constant once a week but she gets very heavy periods).
But there is a part of me - more of a fundamental part - which says if she doesn't desire sex initially then she doesn't desire me, and that there's something wrong. My brain basically flits between calling it "pity sex" and her "prostituting herself out to me".
So basically, I think I'd term this up more as "what should I be thinking?".