"I think she is rushing to leave. I told her I love her so much that I want her to feel free to leave on 3/20. She's planning on leaving 4/17 - the week after my oldest turns 7. That seems pretty rushed to me"
I disagree. How long have you been posting? That's when she said she wanted to leave. But she's still there. My W said she wanted out and she was gone within 24 hours. Look through many of the other threads, their spouses all left in a week or two. Your W has been around for a few months. It's definitely not a rush.
"All my friends feel she is truly done and will not be looking back. I must accept that as a reality. "
It's a reality but not an inevitability.
"Any suggestions on how to make the most of the 3 weeks we have left in the house together?"
Yes. Continue with your changes. Even if she doesn't acknowledge them she still can see them. Be polite and listen to her when she's talking. Don't walk around all mopy and sad-eyed. Live your life already as if she wasn't around. It will be the hardest thing you can do, but you can do it. Don't let her goad you into an R talks or fights. Continue to stand for your M, but don't stand against her. It means to stand for your ideal but not to be confrontational to her about it.
Ask her out to do things together with the kids or even with you if she's up to it with the agreement that you will not bring up anything about the R. You want to leave her with a good impression of you.
Do not initiate any more hugs, kisses, etc. Don't enable her by going overboard to help her. Things like that.
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.