Ds is 14 this year. Mutual split with his dad when ds was about 18 months old (I say mutual but his dad was mentally abusive and had serious issues).
Since then, his dad has had several "serious" relationships, gotten married and divorced and had another two children...one with his (ex) wife and one with his new partner. He has lived in several places, slept on friend's floors, had a bedsit, moved back to our old house, about three rented houses with his current partner. Contact with ds has normally been only when he's in one of his "serious" relationships and it's always the partner who seems to encourage it.
He has never really been interested in where ds went to/goes to school, bullying issues, learning issues, doctors appointments, birthday parties, school plays, parents evenings etc etc. All this has been left to me over the years, no support whatsoever. He once told me that since I had ds live with me then it was "my problem". He pays no maintenance at all, has bought ds one shirt since he started secondary. I ask only that he tops up ds's phone £10 a month, that is all (and he doesn't always do that). He often buys expensive pets and guitars for his collection. He doesn't have any contact at all with the child he had with his ex wife and told me "well it isn't my problem, she can find me when she's old enough".
So, his current partner is lovely. She seems very reasonable and we've actually had a few conversations that exp doesn't know about. From what I can gather he treats her like crap too and I dont know why she puts up with him but that isn't my business.
My ds now spends most of his time in his bedroom on his ps3 (I didn't buy it, he saved birthday and Christmas money to buy it himself). He is either on his phone/our landline or texting, or online on the ps3 with his dad's partner, her brother or her son. He wont spend any time with me, is awful to his sister. He treats us like something he stepped in. When he goes to his dad's he'll do things like cooking with (let's call her Sarah), when I suggest it here he'll laugh at me and bugger off back upstairs. When I suggest any kind of outing he'll say no, he cant be seen with mum...dad is ok, but not mum, he'll have the piss taken out of him if we see anyone from school.
I've asked him over and over what's wrong, why is he so unhappy here but he always says its fine and he's not. Tonight, he suddenly announced that he would like to go to dad's..Sarah had texted him and said she'd pick him up. If i'd said no i'd be the bad guy but I will be anyway. Because I had no clue he was going to stay there his clothes were still on the ironing pile (to be done later tonight) and he hadn't had tea yet (because he wouldn't come down from his room to tell me what he bloody wanted).
In the end I said "just do what you want ds". He collected his creased clothes and off he went when Sarah arrived.
I have done so much for that child on my own and he seems to be so unhappy here with me. I dont know why. I've always given him everything he wanted, years ago I sold my own clothes on ebay (and i'm not talking designer, i'm talking £3 each! and yes, I was working at the time too) because I was short of cash for his birthday. I've never brought random men back here. Our fridge, freezer and cupboards have always been stuffed full of food. He has always been loved to bits and lived in a stable environment. Any problem he's had we've talked about or when he was younger, I sorted out for him. Every day since birth he's been told he's loved.
Where the fook have I gone wrong? (sorry it doesn't make much sense but i'm a bit tearful 
)