An Accidental Faerie Tale (Trium Perfectum #0.5) by Kara Zone:
 
When brooding Max Gilbert meets Aiden Avery, the bright and charming twin brother of his best friend, he never expects to feel the pull of the trium perfectum—a powerful bond that promises connection yet threatens destruction if resisted. For months, Max ignores the bond, determined to keep his distance, but fate has other plans. When their paths cross again, the bond ignites in a surge of magic that nearly tears Aiden apart, forcing them to confront the undeniable connection between them.

As Max and Aiden cautiously step into a relationship, they find themselves tangled in a web spun by Nicolas, a medical student with a dark fixation on Max.

To rescue Max, Aiden must journey into his mind, braving the storm of his darkest memories. But in facing Max's past, Aiden discovers secrets that could bind them—or break them—forever.

In a world where magic intertwines with desire, can they find their way back to each other before it’s too late?