Looking for a story that I read a some time ago.

[662buglebutt]

I am looking for a story that I read a while ago, but I don't remember the genre, the writer nor the title. It was about a guy that bought a house in a neighborhood somewhere on the East Coast and his next door neighbor was a single mom just a few years younger than him with a 12 year old daughter(Nikki?). The young girl attended a private school and played soccer for the school. During her junior year of high school her grandmother became ill and her mother had to go attend to her mother, she left her daughter to stay with this man/neighbor so she could finish her school year with her friends. During this time this gentleman basically taught this young lady the facts of life. Her grandmother never recovered and eventually passed away. After settling the Grandmothers estate her mother decides to sell her house and move back to her old home. The young girl wanted to stay with this man and finish her high school but her mother wound not let her so they moved back to the mid west where she graduated high school.
After college, marriage and 8 years since she had seen her former lover she shows up at his front door and says she has been in town for a conference and wanted to see some old friends before flying back to the West Coast. They had one last fling in bed before she had to catch her flight. About 2 months later he gets a call from Nikki's mother that Nikki is pregnant after 2 years of trying. A few minutes latter he gets a text message from Nikki say that in a few short months that she will be able to finally have something to remind her of the moments that the shared together and for him not to try to contact her because she is on a burner phone and it will be destroyed as soon as she hangs up also attached was a grainy sonogram. He finally realized he had been had.