and results in something more. Possible angst.

Here's one of my faves:

One Special Night by Katrina
AU: All Human. A heated encounter with cynical stranger, William Saunders, on a winter's night gives sensible, Elizabeth Summers a chance to act out of character and leaves her with memories she'll treasure forever. But then, he unexpectedly reappears in her life and wants to pick up where they left off...

Here's one I think you'll enjoy


Over the Summer by SlayerFan

Summary: The New Year is going great for Elizabeth until the day of her first class when she walks into the lecture hall with a professor who happens to be a man who Buffy thought she would never see again. Not only has she had an affair but...


http://www.sinister-attraction.net/stories/s/overthesummer.htm

Reckless Surrender by Ashlee.
More Than Strangers by Sadbhyl.

Gardens of Oblivion by Addie Logan is an amazing read.
Summary: After discovering her husband has been cheating on her, Buffy Summers decides to get a little revenge before she tells him good-bye. However, her plan takes an unexpected turn when the man she meets is more than he seems... (AU, not all human)

For the Sake of the Song by science
Summary: William Pratt has just found out his girlfriend is cheating on him. While drowning his sorrows, he meets a beautiful stranger. But what started as a one-night stand quickly turns into something more as William gets to know Buffy - and her secrets.