^Agreed.
Not only is she completely failing to respect and validate your needs, she turns your needs into some kind of attack on her, which is unhealthy.
Also, her "need" isn't a need at all.
There is no need to get engaged. She thinks she has a need to get engaged, but it's nonsense. What she needs is to feel secure and wanted as she is.
Well, an engagement WILL NOT do that for her. I 100% guarantee this. Thinking that it will is also nonsense.
As well, you don't actually want her as she is. The simple truth is that if she is fundamentally asexual, she's not really what you want, which is OKAY.
Deep, deep, deep down, I think she knows this and I think this is why she's so fixated on you "committing" to her, because she's convinced herself that if you propose, then this fundamental problem in your relationship isn't going to actually be a problem.
Well...that's not how it works.
Again, engagement won't fix anything. In fact, both engagement and marriage will absolutely make this problem worse. Several of us have told you that. Take the warning seriously.
Also, where is her "need" for an engagement even coming from??? It doesn't sound like she's super religious, so what?? Social pressure? Expectation? Does her "need" to get married have literally anything to do with you really? I got engaged because at that age the pressure is overwhelming. That's a completely invalid reason to get engaged, and I feel like a proper idiot in retrospect.
Her "need" for an engagement isn't a need at all, it's a desperate illusion that it will magically make her feel better about something that you CANNOT fix for her.
Meanwhile, your needs are actual, simple, human biological needs that are 100% reasonable...and she doesn't seem to give a shit about them.
Her response "well, we've been fine all along, I don't get why it's an issue now" and "if you need sex, then I need an engagement to even try" and "that hurts my feelings"
She seems to show literally no validation or recognition of your needs or even emotional experience.
What's worse, as several people have pointed out, is that even *you* don't seem to give your own emotions and experience much weight. You're here arguing over and over and over for her side of things. You've barely even touched on your own experience. It's...unsettling to read.
All of this points to a relationship that just isn't as good and healthy as you seem to think it is. It's not just sex that's missing from your relationship, it's communication and mutual respect. As in, it's missing virtually ALL of the cornerstones of a good relationship.
You guys are really great friends. That's it.