Mathilde Madden 
Silver Cage [EPUB ebook] 

Iris and Alfie have been driven apart by the strongest forces in the werewolf world – the powerful thrall of the Divine Wolf – the mother of them all. Now Iris needs to win Alfie back, not just for herself, but because the fate of the world could rest upon it. But the only way to free Alfie from the power of the Divine Wolf is to kill her. Something that could end the lives of all werewolves. Including Alfie himself – Iris true love.