I find it incredible that the Duck has been with your H for so long and doesn't actually have links with his kids.....I just don't get that and wonder why you would remain in a R when that's the case?
I think Mr. P was largely acting out of respect for me. Remember we had a written (but not legally binding) separation agreement. We spelled out lots of things, and one of those was that the kids wouldn't be exposed to the duck while we were M. Not in person, not on FB, not in pictures in his apartment, not by phone, etc. He kept to that, and our D has only been final two months. I think he tried to introduce the duck to D18, but she just wouldn't have anything to do with her. Of the three, she would be the most resistant, probably a bad starting point.
Now, why the duck stays is beyond me. But not my problem.