Well, 2012 started in the same way as 2011 ended - with my exH being a PITA about arrangements for DD.
To summarise - he is obsessed with the idea that we MUST co-parent for her sake; he expects me to have regular conversations with him, and expects me to share information with him about things that might just have an impact on her. DD (11) spends a week with him followed by a week with me. Change over is on Fridays, through school. Until recently, DD was coming to me every day after school even on the weeks she was with her Dad, and he was picking her up from me when he finished work. He changed this a couple of weeks ago without telling me or DD in advance so she now goes to him after school on "his" weeks.
I find DD's Dad is a very challenging and difficult person to talk to or spend time with; he has been described by mutual friends as bombastic and he has a history of trying to bully me into doing things his way. His daily emails are littered with phrases such as "how sad and disappointed he is" that I don't agree with him about one issue or another. He links the slightest thing back to DD, and states that if he is unhappy with the situation between he and I, then he can't be a good Dad to her, so we have to discuss things until he is happy, for DD's sake 
And this is sort of where my question comes from. Is it better to share information about significant life events with the other parent? ExH insists that he needs to know every little thing that might affect DD - but recently, he isn't doing the same thing 
Recently, he has got engaged (DD went ring shopping with them and eventually told me about it - she had obviously been bottling it up), and last night DD spoke to him on the phone and was unsettled afterwards - it turns out that her Dad had told her that they were planning on moving house and she would be looking at houses with them at the weekend.
Should I continue to share details of my life with him, so that he can support DD, even though he's not reciprocating, or should I just adopt a "parallel parenting model" and let him get on with it his way and I'll do it mine?
In the past, he has disclosed some of the fairly personal things I have told him that are happening in my life to other people and organisations - in order to try and manipulate a situation to get his own way.
What does "shared care" and "co-parenting" actually mean? As far as I am concerned, we are not co-parenting, and DD lives with me, all be it with significant contact with her Dad - but he has got really upset about that - he even got a solicitor to write to me to insist that it was a shared care arrangement.
But, when I asked him recently exactly what he expected me to do differently to make it a shared care arrangement he can't tell me - his problem seems to be with the way I think rather than what I do.