The Last Note by Grace McGinty

Harper’s relationship with her mother, Evie, had always been strained and filled with secrets. But when Evie dies of breast cancer, Harper feels lost. There was no more time to make peace and get answers to questions that had plagued her for her whole life.
That is, until Knoxfeld Long, her mother’s stupidly attractive lawyer, turns up on her doorstep with the chance to find out exactly what she’s always wanted to know: Who is her father?
Evie had left her only daughter an expensive Memory Reconstruction, allowing her the chance to live her mother’s memories for a few days, and get swept up in her parents’ whirlwind romance.
But as the delve further into the past, Harper has to ask herself if she really wants to know, or if some questions are better left unanswered.