Beds and Blue Jeans by Nadine Sutton

This is a long novella, available on Amazon. It is set in the early 2000s' a few years ago, and its about the music business in Nashville. Sam is a bar singer, who makes a basic living, singing in the bars. He has a girlfriend, Pattie who has moved in with him when she became pregnant, but their relationship is not working out too well. Over time, Pattie grows up a bit, and Sam who has been unfaithful to her and irritated by her, comes to understand her better.