I'd suggest that it's BS you use her for just sex.
Sex is just part of what you use her for. Just like income is part of what she uses you for. She has a list, but is way too dull to even know it.
She uses you for security, companionship, friendship, sounding board, sperm donor for making babies. Good god, are you blind? Or like most of us, used to seeing the world through the eyes of women who KNOW how to state their objections while WE just obsess over how stupid we are? We're not, really. We're just nowhere near as competent at stating our issues.
We all use each other for various purposes. If wifey is only an outlet for sexual energy, you are that for her, too. If she has no sexual energy she wants to spend on you, what in the hell are you doing wasting your time on her?
Sex isn't essential, like perhaps protein. But it IS essential in other ways. Filling the 'belonging' or 'self-esteem' parts of being human, maybe? You aren't worth my time explaining this. Google is your friend. Search term = "maslow".
What is the value of what you provide? Is it worth more than what you are being offered? If not, and you voluntarily stay, you violate a basic free market concept. Message me and I will send you my bank account info so you can send me all your money. (See what I did there?) You obviously don't have good judgment, and I am really pleased to drink your blood. Thanks!
If you unambiguously convey to her her value, and get less in return, this deficit has to be assessed against the value of your kids, your lifestyle and community. If that doesn't zero, scoot. Otherwise suffer.
No one gives a shit. Not me. Not reddit. Not your mom. Only you.
Wanna be a carpet? Fine. We don't care.
Wanna be a man? Suffer if it kills your worthless ass.
If you and I were in the same room, I'd hug you and literally punch you in the arm.
Listen friend... we all get the same basic training... none.
Life is 7 decades, give or take a few. When you die, that's it. God, Jesus and heaven are pure bullshit, and please, forgive me my dear bull friends! This is it, mofo.
If you fuck up and live unhappy early years, in your own interest, make the later ones good.
Goddamnit, I wish reddit we already virtual reality, because I would man hug you and then, soundly kick your dull ass.
If wife loves you, she wants you to be happy. If she doesn't want you to be happy, she doesn't love you. Simple, huh?
Sex makes you happy. It's part and parcel of the bargain. Sometimes, it takes effort.
She is telling you every day that you are undesirable, unworthy, unimportant, ugly, unattractive.
Tell me again.. how is this a good deal for you?