That is what we call the triumph of hope over experience.
Who's "we". ;)
Hope is one thing. Failure to learn from the past is quite another, especially when you're putting yourself in a position to suffer the fallout - as a spouse certainly does.
I may hope that the past experiences of a pervert priest may be in his past, but I would certainly exercise poor judgment if I were to, based upon that hope, let him babysit my children.