She has come back to you because of her personal reasons. That guy might have cheated her or knowingly she might have kept physical relations with him. At present, out of your love you have accepted her physical relations but do you really think that it does not matter to you? If you think that it is acceptable to you once and for all then you should think further. If you are not capable of establishing yourself without your parent’s support then you should rethink before you go ahead.