No need to be brutal. We all have set backs. And who would not want to belief it was all just a big mistake - the person we have history with admits to. Im sure the validation felt healing and assuring. Its hard to accept that are spouses are just narcissistic, entitled, lying pos. Sometimes it takes a fool me twice to really accept it cause we project our own feelings onto them.
But now its time to move forward. Moving forward is not with him. He is not honest. He is not loyal. He is not committed. He does not have real feelings for you. He might say he does, but his action have not and do not.
You will be fine. Focus on making your life good. I think when our lives our empty in some way, it makes us more suseptible to filling the voids with a broken relationship.