My ex is abusive, selfish and downright unkind sometimes but, for some reason, when he gets in touch and there's a glimmer of hope of rekindling stuff (even though I know I shouldn't want him at all), I feel like I want to sort things out - regardless of the horrible shit he's done to me in the past. 

Like, in my head, if I just let it go and move on, then it's a failure on my behalf? 