As far as talking to D about poly is concerned, there's a post about it from Ppercs at:
Poly is in the news all the time. You can find updates at:
Other helpful sources of information are:
" by Tristan Taormino
Franklin Veaux's poly pages
And there is a lot to read right here on Polyamory.com (e.g. the Golden Nuggets board
). Somewhere amongst all this reading material, you might find something that would help you introduce the topic of poly with D.
You should ask D where his sadness is coming from, although I suspect it's because he figures that if you love J, then you must not love D as much. Love is not a finite resource, but somehow D must come to his own epiphany about that.
Hope some of this helps.