I envy you sol that your able to spend that type of quality time with your D. For circumstances beyond my control, my time is limited but I try to make the best of it.
Sometimes, I secretly wish my stbx would have completely gone off her rocker and left my S7 with me, but I know that's not in his best interest. As is stands now, she's only partially insane, but still a good mother to him.
Your W is going to wake up some day and realize to late what she's missed. Your D will be grown and the W will wonder where the time went.
"It is curious that physical courage should be so common in the world and moral courage so rare." -Mark Twain