(Her father loved her in the super-sexual way that is far too sublime for incest.)
The narrator reveals that in fact her father had sex with her as a child, and she remembers it as "too sublime for incest" - sublime meaning elevate to a high degree of moral or spiritual purity or excellence. So her affection for him and good relationship with him has clouded her memory and made the incest in her mind morally right. This is the reason why she loves Al, has in a way been trained by her father for Al, but Al is not her father.
