Your daughter’s mental and emotional health is paramount. Currently, someone who should be important in her life is probably allowing other people’s needs to cloud his judgement. This is as much a tragedy for him as it is for both your daughters. From a practical position, are there any other people in his life who may be able to advance the discussion that seems so difficult for the two of you to have at the moment? Perhaps a parent, sibling or friend might be able to take the conversation in a new and more helpful direction? You can’t escape from the legacy of your own relationship with your husband and it’s always possible that the circumstances of whatever happened to end your own marriage to him are alive and well and preventing either of you from being able to speak together in helpful ways. That’s not a criticism of either of you by the way – it’s simply one of the things that can happen post relationship break down. Obviously, the best thing would be if you, he and his new partner could talk together about what is in the best interests of the children. Children often get caught up in the unfinished discussions between adults, often with very painful results. Maybe that’s happening here. But whatever else you do, keep reassuring both your daughters equally that they are important and worthwhile people. The trick here is not to over compensate with your eldest and end up inadvertently treating your daughters differently as your husband is doing. Of course, another way of seeing this (and certainly a point for your husband to consider) is that through his treatment of your eldest, he is also wounding the youngest by potentially making her feel guilty that she seems to be the chosen one at the moment. In time, he may realise the problems he causes by doing this and decide on a restorative approach with both of them.