Don't be too hard on yourself, we all backslide. It has taken me 2 years to get the DB stuff right and often I still backslide.
Try to not let him see he is pushing your buttons. I only text my ex so it gives me time to cool off.
The best way to get along is to just focus on the kids stuff that is necessary. Don't talk about anything personal other than just being a kind person. Don't forget to validate (for the time being) what he is saying to you as apposed to fighting with him. Remember the saying "it better to be happy than right". Think about every thing you say to him with this filter: "Is this going to make the situation better or worse?" I might suggest that most of your dialogue could be in emails or texts.
You have asked him for date and he ran so don't do that any more (2 x 4). Just show him a positive, fun person and hope that he wants to come around.
Be cautious with the "relations" thing. Sometimes it brings people closer but most of the time it just hurts one of the people deeply.
(((((We know how hard all of this is))))))
Me/W: 46/36 D7.6/S6 T/M: 7.5/6.5 Bomb 12/05/07 D final: 03/03/09