Wind & Wildfire by J. D. Evans

This is a prequel to the Mages of the Wheel series (which is amazing) and I read it after reading book #4, but I think you could read it any time after the first book Reign and Ruin. I almost didn't want to read it because I just didn't want to have a shred of empathy for Behran, but ultimately broke down because 1) I wanted to know so much more about Naime's mother and 2) I ran out of other J.D. Evans stuff to read. This entire series is top tier fantasy romance and well worth your time.