I get the question all the time, usually from someone I know, phrased in a variety of ways:
Did it really happen?
Are any of the characters based on specific people?
Your descriptions of ________are so vivid and realistic. Are they based on personal experience?
I've even been asked if the jumping girl on the cover is me.
This curiosity is human nature, of course, and inevitable that my protagonist, Erica, used to live in New York (like me), has four children (like me), and shares some personality traits with me. Ethan works on Wall Street, as did my husband. We used to live in New York, and moved.
I also have a very active imagination.
These questions are uncomfortable, but the very essence of publishing any fiction that deals with real human emotion is akin to dancing naked across a stage. I've already exposed myself as much as I want to. If I wanted to totally differentiate what is "real" and what is not, I would not be writing behind the veil of fiction. My answer to all these questions is basically this: None of the characters are based on specific people. Many of the events are entirely fictional, and in other cases I have taken great liberty with the facts. There are a few people who may recognize parts of themselves in the story; they know who they are. That said, the settings are ones I know intimately, and the emotional truths are real.
No matter how many times I deny that this or that prurient detail REALLY HAPPENED I realize I won't be totally believed. A nugget of doubt will remain, and I'm OK with that. There's a lot of people running around thinking I'm more interesting than I really am.