SoAsh...I feel really sad for you, I know you are in agony.
Are you spiritual? Do you belong to a church? If not, would you consider joining one? Church is a great place to go and sit in a pew and cry your eyes out. If not a church, there are help-support groups for divorcing people.
Please be gentle with yourself, but at the same time, try to stop focusing on how you ruined it, or that you would "do anything to get him back". Those thoughts are not going to help you.
Maybe think of it like a car accident where you were the driver and you hit a pedestrian, and that you know you were not paying enough attention when the accident happened. You accept your part of it, but you also know in your heart you would never have "meant" to do that. At the same time, you cannot expect the pedestrian to make you feel better. He/she has their own pain to deal with and yours is irrelavant to them. In that type of case, you have to get your own closure with it and stop focusing on "anything to get them back". Instead, you pray for their progress and recovery, and you pray for your own. The only thing that helps is time and acceptance.
A question, why are you pretending everything is ok? If your world is falling apart, you need to be open about that so that your friends and family can help you with it.