I read this novel many years ago that I am trying to find. Can't remember name or author but the story goes something like this: Story starts with private detective calling male character and saying "I've found her". They were involve and for some reason she disappears. It is about 18months later and he has found her. He shows up there and she is hiding a secret. She has had a baby for him ( I think a girl with a name something starting with M) anyway when he finds out she had the baby for him and the child is staying at her friends house he puts his hand through the wall and was crying. Can anyone help me find this book. Book either MB or Harliquin

Can you remember the time it's set in, or the place?