Quote Originally Posted by Penarth Blues View Post
My advice is to do nothing and just wait it out. The girl will be going through her own peculiar hell at the moment of not knowing who she is or what she wants, plus the pressure of crucial exams, an uncertain world of work/University and the insecurity of already having one parent leave her.

For the longer term sake of your relationship with her and her Mum, you just need to let it go until she moves out. Only then will she realise what you've both been doing for her and at that point you can start to discuss things like adults.

I'd make sure that you and your partner spend quality time together at least once a week where the girl is not present if you can - and DON'T talk about the daughter during this time.
That could be a long wait. In 2013, the average age of a child leaving home was 27.