I think when you're validating and listening that's good. Something like the following may help- "I understand you're upset that I am running now and would not run with you in the past. I can't go back and run with you in the past, but you're welcome to join me on my runs now. I am not running to upset you, only to improve my health."
Others can chime in if that would work, I guess we don't know until you try it. Another choice would be to get her to specify why it is that makes her mad, is it the running, or not spending quality time with her in the past? Is running a symbol for a bigger underlying issue and she chooses to address running rather than lack of quality time together before? I think you can dig a little bit on that topic if you get the chance again.
H: 29 WAXW: 30
Bomb Drop- 9/9/13 Negotiated Settlement- 5/9/14 D Final- 5/21/14 XW has breakdown in attorney lobby- 5/30/14