Even so, I'm glad Owen retconned Ianto at the end, because remembering was destroying him. No one should have to live with memories like that, and worse, Ianto knows he destroyed his own happiness by demanding to remember. And Jack... he's not usually that monster, he genuinely cares about Ianto but there's always going to be that darkness inside him and if it gets out it makes him do terrible things. But Jack's a victim too, he was turned into that monster by being tortured himself.

Ianto's self-destructive tendencies melt away when he's with Jack, and Jack keeps a rein on the monster within when he's with Ianto. They're good for each other, as long as Ianto doesn't remember.