The Lord of Whispers by Cameron Kay

Alarie clawed her way out of her small hometown and to the High Court in the big city. It was a fairytale come true complete with dashingly handsome lords…except that at the High Court flirting is treated like a blood sport, the normally immortal fae and their magic are dying for reasons beyond anyone’s control, and the Kingdom is on the cusp of a class war.
Alarie finds herself in a once-in-a-lifetime opportunity to learn at the hands of High Lord Vitruvian. The high lord, second in power to only the King, will stop at nothing to save the Kingdom and he is very, very protective of what, or who, is his.