Why wouldn't you thank someone for something they do? Sounds to me that your D simply wants you to be kind and respectful of her H.
As far as our exes...
The woman my X is dating now (who isn't OW) has done some wonderful things for my S. My boyfriend has done equally wonderful things.
My stepfather, who was OM, has been a kind and loving parent to me for 30 years. Even through the years when I didn't want to see him as such.
If I had not eventually accepted him, I would have missed out on a lot of love and I would have robbed my S of the only grandfather to hold a consistent presence in his life. As well as two kind hearted great grandparents.
That would have been a shame.
There comes a time where we should try to realize that standing on a soapbox Indefinately is more damaging to us and others than it is to step off of it and allow forgivness and peace enter our hearts.
JMHO.
I hope you have a very joy filled Christmas season. Peace be with you, Irma.
Cat
"Acceptance doesn't mean resignation. It means understanding that something is what it is and there's got to be a way through it."--Michael J. Fox