The MC's role is usually that of the background character in other stories. As horrible as it is, I'm interested. That character that suffers with no happy ending in sight is real. His strength is real.
I think it's a bit more bearable because the incidences are shown as vignettes. It's not told in 'real' time or chronologically so the effect of the violence suffered by the MC is not as severe. Usually I can't bear this kind of violence but the way it's delivered is not pornographic. If that makes sense.
(So far) we're not made to understand or sympathize with the abuser either. Except maybe the present one a little.
So for me, it's bearable... barely.