Hare Krishna!. Prabhu, Get her to some Guru and make her understand about the sanathana dharma. She will not do that if she truely understands the sanathana dharma. Whatever the case may be,please do not get depressed under any circumstances,be happy all the time. I don't see any reason to get disappointed since these relationships are temporary. We should always follow the path of dharma,feel whatever is happening is good for us only and at the same be surrender to god(krishna). Do what all you can do to make her realize,rest leave it to god. Upbring your children as responsible persons and make them follow the dharma and great persons in this world. Also do some 20 mins meditation in a day, read and understand bhagavad gita,bhagawatam. All the best.