It's important to forgive ( ourself and others), because otherwise we are chained by that anger or sadness, chained to the negativity that holds us down. Forgive not because he deserves it, but because you do.
I think if you are able to forgive the transgressions, you will not feel so knocked over when you discover more of them. For me, the forgiveness starts as an intellectual choice that grows into an emotional felling of forgiveness over time and repetitions of that choice. Kind of like fake it till you make it.
And I definitely relate to what you are going through, thanks for sharing.