The Vampire Who Loved Me by Teresa Medeiros

From the publisher (source: The Internet Book List):
From the publisher
Julian Kane is back in town.

Once, as a girl of seventeen, beautiful, headstrong Portia Cabot saved the life of the dashing vampire Julian Kane - who marked her forever, then left to go in search of his soul. He returns five years later to find the enchanting young girl he left behind grown into a bewitching woman with a woman's heart... and a woman's desires.

Portia quickly discovers that Julian's seductive and forbidden kiss can still make her crave the night... and his touch. But the Julian who has returned to London is not the vampire she remembers. His fruitless pursuit of his stolen mortality has reduced him to drunken debauchery. And a recent spate of murders makes Portia fear that the man she has always adored may truly be a monster.

Julian knows he must drive Portia away -- but his passion and hunger for her grows more irresistible every time they touch. For years he has fought the temptation to embrace his dark gifts, never realizing that Portia's love may give him the most dangerous gift of all... a reason to live...

This book is part of the "Cabot" series.
Here are some other books from this series: