or at least get 50/50 custody
DS has always lived with me. I split with his dad when he was 6 months old and for first 5 years of his life his dad was not interested at all. He rarely saw him (despite me trying to facilitate contact), and also didnt contribute financially. In fact, for 3 years, he moved 200 miles away to go and live with a woman he had met. He came back to the town where DS and I live 5 years ago and since then he has has had regular contact (friday after school till sat evening) and also been paying a pittance
DS is ten now so I am applying for his high school next week. A few weeks ago DS dad suggested DS apply to a high school near him, that his step brothers go to (his dads DP's kids). its a pretty good school so at first i was happy with it and was going to apply there
However, I have considered it and actually, it doesn't work for for DS to go there. I have 2 other younger DC now to get to school, and I also work. There are closer schools that I would rather him go to and there are lots of other reasons I think it will be better if he goes to a more local school. DS does not seem bothered either way.
DS dad seems hell bent that DS should go to this other school though. He insists that DS "really wants to go to" there, and keeps saying things like "maybe DS can sleep at mine a few days a week and it will make it easier" . Today, I overheard DS tell someone "my dad says i will be living with him half the week when i go to high school". this has NEVER been mentioned to me by DS dad and i would NOT be ok with this!
It just all sounds to me like DS dad is trying to work on him to try and persuade him that this school is really really great, selling it to him by saying he will be at the same school as his stepbrothers, and work towards having him for more of the week and possibly even leading to having him 50/50 or more. And knowing DS's dad like i do, i would put money on it being to do with his child maintenance payment, as it would go down considerably if this happened.
I don't want to have DS any less than i already do. His home has always with me and his little sisters and his step dad! who by the way has been the one constant in his life (equal to me) since he was 18 months old. Funny enough when DS was tiny and we were applying for his primary school his dad couldn't have cared less as he was 200 miles away and had no idea where his own son was even going to be going to school!! 
I hope this all makes sense, I want to tell DS dad that I won't be applying to the school he wants DS to go to. Any advice would be much appreciated :(