Father In-law big issue?

Ok i have a beatiful wife and addorable daugther id do anything for them in the whole wide world, but i hate my wifes father with a passion and this is why , While back (in my wifes teenage years) her father use to do cross country driving and he took his daugther (which now is my wife) for a couple weeks. Well her father was depressed and molested her...... not gonna get into details but anyways he said he was srry that he wasnt in his right mind blah blah blah , my wife felt srry for him and still talks to him this very day but i hate the scum bag , she thinks she can still build a good relationship with him which i dont see how that can happen , idk what to do , this has affected our relationship alottttttt and i think shes emontionally disturbed , Am i selfish for hating this bastard? and not wanting our kid around him? i know his a grandfather but stilll what if one day shes alone with him and im not around.... u know what i mean? idk but could i get some advice from some people?