What your husband did is out of male instinct. Although he has to blame you for that, so he can save him from question why he did that? What you did might be out of your need to get love and affection or may be revengeful act. Now, probably you are feeling guilty from within. Your relationship with your husband has reached to point of indifference and that is even worst then quarreling. Revival is difficult but not impossible. Stop all contact with your friend and try to concentrate on your son, husband and family without any complaints and guilt. Accept what ever has happened without questioning and analyzing. I know, this is not simple but you can always keep on trying. With passage of time, things may start coming in to shape.