This is the series by Sara Douglass:
This series is two trilogies, beginning with the novel The Wayfarer Redemption. It takes places on a world that has different races of humans. One race, the Icarii, can fly and do magic through song. The male protagonist, Axis, is of this race. However, through some plot contrivance I can't fully remember he's not able to do it or perhaps unable to do it well until he meets and falls in love with a wingless woman from another of the races, Azhure. Even though Azhure is not Icarii, she either can do magic like they can or can do Icarii magic with Axis only. There is another woman, Faraday, who drives a lot of the early plot (the first 2 novels I believe). She is in an abusive relationship with the leader of the Achar people who hate all magic and have tried to exterminate the Icarii. She is the female protagonist in the first novel and a lot of the book is about her, she is a surprisingly well developed character for a book of this type that also has a male protagonist. The first trilogy of the series (Wayfarer, Enchanter, and StarMan) works out how Axis and Azhure get to be together permanently, overcome evil leaders of the human races, some kind of world destroying demon, and start a family. They end up ruling the Icarii people as the SunSoar family.
The second trilogy jumps forward a bit to the next generation. The eldest of the SunSoar children is grown and an outcast from his people for being evil. There is a younger son, Caelum, who is grown or nearly so, who must take over the Icarii leadership after his parents ascend to the astral plane to live in love and peace forever feeling that they have done enough for the world. This trilogy is really twisty and it's difficult to explain. The main thing is that the older brother was under mind control by a demon from when he was still in the womb. He is not really responsible for the evil things he did. He is able to communicate telepathically with the younger brother and they end up working together, against the laws of their people and the commands of their parents, to avert an apocalypse that would have destroyed all life on the planet. The enemy they fight was the true Big Bad behind the enemy their parents fought in the first trilogy. This enemy is the demon who controlled the older brother until he was able to secretly escape some of the mind control and begin making some of his own small decisions. Faraday makes a comeback in this trilogy as well and has more power. She also gets treated a lot better.