I don't think it's untrue to say asexuals and demisexuals face a lot of judgement and misunderstanding. They do. Most people aren't aware that asexuality is a spectrum and it varies from person to person.
Edit: if anyone is interested in learning more about this topic, I recommend this book by journalist Angela Chen
It's okay to choose to do that.
But please put the down the baseball bat of guilt and shame.
You were a kid. A kid who was ill prepared to deal with this kind of encounter.
If an 18 year girl told you this story, would you think?
You're not a kid anymore. But that kid you used to be sure could use some compassion.
It's unreasonable to believe a kid should be able to hold up under withering, non-stop coercion combined with the insidious psychological and emotional abuse she heaped on.
All I see is a good kid in over his head with a shark. Whatever her own emotional woundedness was/is, it made her dangerous to your wellbeing.
I'm glad you were able to free yourself and are in therapy.
Don't give up on yourself.
You might be interested in an ACE relationship. It may fit your needs.
I recommend this book to get an idea of what the ACE spectrum looks like.
Ace: What Asexuality Reveals About Desire, Society, and the Meaning of Sex https://www.amazon.com/dp/B07Y7H1WT9/ref=cm_sw_r_apan_glt_5B6N2G0S2D430KH2H9SA
Have you considered she might be on the ACE spectrum? Google some terms like gray ACE. A good book is this:
Ace: What Asexuality Reveals About Desire, Society, and the Meaning of Sex https://www.amazon.com/dp/B07Y7H1WT9/ref=cm_sw_r_apan_glt_8DRN3A79F5RKC2XMEDRV
Of you decide this way off the mark, try looking into Sensate Focus. It's been helpful in many a "dead bedroom" resuscitation.
Maybe it's about how her sexual motor works (breaking system and acceleration). You two can read this together and see if it resonates:
Come As You Are: Revised and Updated: The Surprising New Science That Will Transform Your Sex Life https://www.amazon.com/dp/B08BZWXK9J/ref=cm_sw_r_awdo_navT_g_VFKR8GRB13AGGVCFXTQP
Anyways, just a few ideas that are outside box to maybe give you a new a way at approaching the situation.
Read this and see if it resonates...
Ace: What Asexuality Reveals About Desire, Society, and the Meaning of Sex https://www.amazon.com/dp/B07Y7H1WT9/ref=cm_sw_r_apan_glt_8DRN3A79F5RKC2XMEDRV
Checkout writings on gray asexuality too
Check out this book first. It might reveal answers.
Ace: What Asexuality Reveals About Desire, Society, and the Meaning of Sex https://www.amazon.com/dp/B07Y7H1WT9/ref=cm_sw_r_apan_glt_5B6N2G0S2D430KH2H9SA
You might be on the ACE spectrum.
Try checking out this book
Ace: What Asexuality Reveals About Desire, Society, and the Meaning of Sex https://www.amazon.com/dp/B07Y7H1WT9/ref=cm_sw_r_apan_glt_5B6N2G0S2D430KH2H9SA
Or it might be you need to have things in a very particular way
Come as You Are: The Surprising New Science that Will Transform Your Sex Life https://www.amazon.com/dp/B00LD1ORBI/ref=cm_sw_r_apan_glt_XM4NJAME30VZV1RS2H2E
The thing about a satisfying sexual relationship is it's a lot more complicated than the biology.
Think about your fantasies and masturbation. Is your partnered sex anything like your solo sex? There might be a clue in the answer.
Remember, you two are supposed to be in this together for both of your pleasure.
You are not required to have sex you don't want or don't like. No one is.
This one is quite excellent:
https://www.amazon.com/dp/B07Y7H1WT9/ref=dp-kindle-redirect?\_encoding=UTF8&btkr=1