I am not sure I can understand your question. I assume that in the past for a period of time you and your girlfriend were happy together as you have kids. So you need to bring back from the past into the present the happy times like a movie in your mind. Your girlfriend is free to make her decisions about her life. However, your positive attitude will impress her and maybe make her consider that she would be happy herself to be part of your happy life. I hope it helps.
