Is there any danger in letting him think that I'm in much better shape than I actually am? For instance, will he think that I'm doing better without him, so it was okay for him to walk away?
No danger. This is what you are TRYING to convey. The purpose is to make him rethink. He knows you were a mess emotionally before he walked out. Now imagine his thoughts when he sees you are upbeat and happy. He is GOING to wonder why. What happened to make such a change? The more he thinks about it, the more he thinks about you. And if he thinks you are moving on without him, it takes CONTROL from him and he is no longer in the driver seat. Huge difference in how he handles himself.
I am not saying he will come running back because of well written email. But he will definitely wonder. As for how to convey PMA over email, you can do it with smiley faces, exclamation marks, etc. For example...
"OMG, you would not believe how crazy and awesome last weekend was when I went out with some new friends!!!
That conveys PMA, GAL, happiness, and mystery all in one simple sentence. And since it is an email, you are not put on the spot where you have to elaborate. If he replies asking for specifics, you can ignore it. He does not get details. He just gets to know you had an awesome fabulous time. If he wants details, then next time he can take you out and get details first hand.
Me: 42 W: 32 Married 7 years together 8.5 S1: 7 S2:7 Bomb #1: 09-16-13 Recon #1: 11/13 A discovered 04-03-2014 W filed D 05-19-14 but never served me I filed D 12-02-2014 S 05-31-14 Divorced 5-19-16