In this particular case, I'd query various people for an answer, on the Community board here at Medhelp, and the sexuality expert forum as well. There may be multiple axes to your problem.
People vary in terms of the nature and extent of their sexual drive. It may be that you never had much of one, and that now, reaching middle age, and perhaps becoming peri-menopausal, it's just gone down quite low. On the other hand, if you had a larger sex drive, and then it diminished, you may want to ask when, and did anything happen in the same time frame. Your husband has his own needs, and if his libido is large, I can understand where the two of you get into trouble.
If it's a straightforward and biological problem, you may want to consider visiting your doctor and seeing whether one of the many meds now out for this so-called “female libido” problem might actually be appropriate.
However, I get the sense your issues with your husband are more extensive. You're thinking about divorcing him. Is there something about him that is turning you off, beyond his sexual demands? Are you just bored with him after twenty-four years? Personality issues you don't like? Has there been anything smoldering under the surface of your relationship over the years, that's coming out around the sexual stuff? If there is such, this is the time to understand it, then see where you go from there. I suggest taking it one step at a time, and not doing anything impulsively.
If you'd like to discuss this further, reach me with some more information about the nature of your discontent, and we'll take it from there.
The sex life you described is similar to what my wife and I had for the first years of dating and then 7-8 years of marraige. Then the sex started to reduce and we started having problems. We got close to divorce. But I would not say that we got close to divorce because of the lack of sex. More like the problems we were / are having are a sign that there is a problem underlying our relationship and that is causing my wife to not want sex.
The fact that you mentioned divorcing him leads me to believe also that there is something deeper than just a lack of sex drive.
It's easier for me to comment here since I can remember whats been said... You mentioned that your husband still wants sex but you dont. I can tell you from MY experience that sex is VERY important to me and my relationship with my wife. Whenever we are not having regular sex, I start to feel detached and distant from her. Like we're "house-mates" instead of "lovers".
I know that sex is healthy. I'm also pretty sure that for me having sex boosts my self-esteem, boosts my emotional connection, and makes me feel masculine.