Sigh... why don't you get a bit more educated?
Man & woman are wired differently. Man wants sex to get his rocks off, woman wants sex out of love, to bond.
If a relationship is healthy, and there is such a thing as bonding, it will change for a guy too, it will also be bonding to him and both will happily enjoy their sexlife and relationship.
What happens often though -because men don't know this, aren't educated on this- they begin to treat their woman differently after a while. For a woman her interest in intimacy with a man who doesn't seem to love and respect her anymore shuts down.
It's a reciprocal thing: you love and cherish your woman, she's willing to share her Sacred temple with you and shower you with love and adoration.
If there's a spanner in the works in that part, woman doesn't want sex. She DOES, just not with a man who doesn't love and respect and cherish her.
Many will resort to masturbating when the man is downstairs or gone.
The same happens when a woman loses her respect for her man. For me this happened when my ex husband didn't treat our eldest right.
I can NOT love and respect a man who's like that and I certainly can not offer my femininity -the most intimate gift a woman has to give- to a man like that.
That didn't mean I didn't want sex, lord knows I did, just not with him. And no, I didn't stray, I'm way to loyal for that. But then you find other ways OR get incredibly frustrated.

A woman is not your personal private wh0re just because she married you. If you start treating her that way, expect that of her, it's over.

And to put the record straight, there are a whole lot of men who cannot please a woman. They aren't interested in finding out what makes her tick, they do what they did with their ex(es) or what they saw in porno movies.
But every woman is different, finds different things pleasurable and arousing. you have to make the effort to find out. Most don't. They don't even THINk that they could get it wrong.

Another thing... many cannot properly penetrate as their thing doesn't get hard enough anymore. This is often to due to a weak pelvic muscle, which happens more and more as many have jobs that have them sit all day long. Then they get home and sit on the couch with a beer. Weak pelvic muscle stops a penis from getting really hard.
When that happens, a woman doesn't feel anything anymore. Pleasure gone. And it's like "wake me when you're done" for the woman and eventually she'll get fed up with the BS. If a man cannot do it properly, it's just a nuisance. Like I said, we're not private wh0res to serve the man to get his rocks off.

I know that many women have higher sexdrives than men. But if the stuff I posted above isn't right, she'll shut down. And she CAN get utterly frustrated as her high sexdrive doesn't go away. It just cannot go somewhere.
And since we don't just have sex to have sex... some can, most cannot. We're not men. So get your own chit right, how you treat her. And make it about HER, not about you trying to use her for your lust.
Sex is about love so both enjoy it. If you cannot do that, get a divorce and stick to hookers.