I assume we're talking about one specific book titled 'Lost Love', because honestly, I can think of at least three novels just off the top of my head with that exact title, plus a few with close variations. Without knowing the author, it's a total shot in the dark. I recently read a contemporary romance called 'Lost Love' by a relatively new author, L.J. Hart. The main character is Anna, a woman who returns to her coastal hometown after a decade. The key figure from her past is Ethan, her high school sweetheart she left behind. The story hinges on their reconnection, with Anna's controlling current fiancé, Mark, serving as the primary obstacle. There's also Anna's wise, no-nonsense grandmother, Maeve, who provides a lot of the grounding advice. The entire emotional weight rests on Anna and Ethan figuring out if the love they thought was lost can be resurrected, or if it's just nostalgia. Honestly, the fiancé felt a bit like a cardboard villain to me, but the small-town atmosphere and the descriptions of the old lighthouse where Anna and Ethan used to meet were done really well. It made me think about my own 'what if' scenarios from years ago, which is probably why the book stuck with me more than I expected.
If you're asking about a different 'Lost Love', like the historical one by Mary Lancaster or the paranormal one by Harper Black, then the cast is completely different. That's the frustrating part about common titles; you really need the author to pin it down. In the Lancaster one, it's all about a widow and a sea captain in Regency England.