So sorry for your loss...The children will come around in their own time..Do the best you can to not pressure them into calling her Mom....In time they will come to relize that she is not taking their mothers place and that you do not want them to forget their mother, they will come to terms with the loss and then except your new wife as their mom.........but it will take quite abit of time....my best to you and your family.Time heals all things.