calel,
I'm sorry but if there was anything going on there you would be together. She used the kids as an excuse to call it off as a way of trying not to hurt your feelings. No one ever tells anyone the real reason why they are calling it off. You should accept her reason the truth might hurt more. Besides the important thing isn't that she used the kids as an excuse, the important thing is that she wanted to end it. You might be able to stay friends but it might be on her terms because she does have the kids to think about. If you still feel so strongly about her why not write her a letter explaining how you feel but that you won't push for anything unless it's what she wants too. Don't text, don't email, write a nice but not mushy letter explaining your feeling and that you think there could be a chance for you both. If she does not respond or her response is not what you would have liked, try to accept it and make plans to move on with your life.