I think by "that" he means the author's: "All I could think was how repulsed she would feel if she ever saw [real me] ... I just could never get past how I fee

I think by "that" he means the author's: "All I could think was how repulsed she would feel if she ever saw [real me] ... I just could never get past how I feel about myself, and see myself, relative to her" That's not healthy, it's almost uncertainly untrue (we all have bodies!), and it's something therapy could help with.