Yes forgiveness is hard and forgetting met not be possible.
But we do say our father, who art in heaven hallowed be thy name, your kingdom come your will be done on earth, as it in heaven, give us today our daily bread, forgive us our trespasses, we will forgive those trespasses again us.
Now that is hard to forgive and forget, how will God forgive us.
In Jesus' prayer I see forgiving our debtors as the fruit of receiving Jesus' forgivness not a prequisite.
Ok, may God help us, because this issue is very serious, which we must learn.