Silver Dragon series by Katie MacAlister [epub,mobi]

Playing With Fire (Silver Dragons #1):

Starring the Dragons Of The Aisling Grey, Guardian Novels

Gabriel Tauhou, wyvern of the silver dragons, has found the one woman who can withstand his fire. Too bad May Northcott is already bound to a demon lord. But when the demon orders May to steal one of Gabriel's treasures:An immensely important relic of all dragonkin - Gabriel has to decide which to protect: his love or his dragons.

Up In Smoke (Silver Dragons #2):

Where there’s smoke, there’s one hot New York Times bestselling author.

Though May Northcott’s heart belongs to Gabriel, leader of the silver dragons, being stuck in Abaddon has significantly cooled down her love life. Especially since a demon lord is trying to woo her. Looks like May will have to barter to gain her freedom and fulfill her destiny by Gabriel’s side...

Me and My Shadow (Silver Dragons #3):

May Northcott is at the end of her tether. Her demon boss has moved in and is making life hell. Her scorching hot dragon lover seems to think everything can be solved with a fiery kiss. And worse still, she's being shadowed by her ditsy twin sister - a naiad who simply can't seem to stay out of trouble.