Mighty - although normally I would not recommend that you engage with your ex in any way, this might be an occasion for a short, blunt communication, something along these lines:
"Dear Ex - It has come to my attention that you are attempting to blame D's attitude towards you on my interference. Rest assured that I do NOT badmouth you to the kids and have NOT tried to obstruct your relationship with them (in fact, you may remember, when you first left, that I encouraged you to see them more as they were feeling abandoned by you).
Unfortunately, it is the facts of the case - you fathering a child with another woman, lying about it, coming home and getting their hopes up only to leave again - AND your lack of consideration of THEIR feelings that has resulted in their current attitudes towards you, NOT anything that I (haven't) said to them.
If you want to repair your relationships with them, you will need to do it by putting THEIR feelings first, not forcing them into a relationship with your new family, making them a priority, and recognizing that it will take a lot of time and patience on your part for them to learn to trust you again. I sincerely hope that you can do that. You will not achieve that by falsely implying that I am the cause of your bad relationship with them.
