In my experience hearing it is more “failing to hook up with” than “screwing up the relationship with” regrettably. A lot of people seem to think autistic girls are easier to manipulate into sex than others. It could absolutely be the more innocent version but in my experience that phrase is usually pretty indicative of the stereotypical “pickup artist” mindset.
Classic Lavender Marriage is the easy answer. In my wife’s case she is deeply intimidated by pretty women so she has enough trouble talking to them. She couldn’t flirt with one to save her gay ass.
Her not being attracted to me like that is fine by me since I’m ace. We’re basically just besties on a permanent sleepover that we formalized for tax purposes.