Oh love I've been there and it's hard to believe me but the years go so fast and she won't have to go forever.
My ds is now 15 and I separated from his dad when he was just turned 2. Things were bitter and nasty for a long time. He put girlfriends first, was constantly criticising me and ds hated staying there but his dad bribed him with a season ticket for their premier league team so then ds thought he was fantastic.
He didn't provide so much as a pair of pyjamas for him though has always paid maintenance.
When ds was 8 he was diagnosed with ASD. His dad was at the meeting with me when we were told but still refused to acknowledge it. Relations were better at this point but he was still an arse.
Ds asked me once how old he would be before he got to decide if he stayed or not and I said 13, he was around 10 at the time.
So 13 came and ds said he still wanted to see his dad but not stay. Ds's dad does not have parental responsibility as ds was born just before the law changed so for the last 2 years he goes there but doesn't stay over.
Their relationship was never close but in the last 2 years it has flourished. He took ds abroad this year, we got on well and things are ok. I would never have believed that all those years ago.
It's so tough. The other reason i responded is that i have a 7 year old dd too so could imagine how you feel. If her dad continues the way he is then the loss will be all his. Dd is very lucky to have a lovely mum.
Very best of luck op, relax and breathe 