You can try fanfiction websites like FanFiction.net or Archive of Our Own. They have a large collection of Twilight fanfictions, and you might be able to find some really great ones with the 'never enough' quality you're looking for.
Since this isn't a widely known novel title that I'm familiar with, I can't tell you the author. It could be an indie author or someone just starting out in the writing world. There are so many novels being written every day that it's difficult to identify the author without more context.
Perhaps it's about how love, while a powerful emotion, is often insufficient to sustain a relationship without other elements like mutual respect, understanding, and communication. In the novel, the characters might face situations where their love is tested, and they realize that just loving each other isn't enough to keep the relationship intact.
I'm not sure as I haven't read the novel specifically. But usually, in a novel with such a title, there could be a couple. Maybe a man and a woman who are deeply in love but face challenges that show love isn't sufficient.
The main theme could be the complexity of human relationships. 'Love is never enough' might imply that other elements such as trust, respect and communication are also crucial in a relationship. In a Chinese novel context, it could also be related to cultural values and how they affect the perception of love. For example, filial piety might sometimes conflict with personal love, making love not sufficient on its own.
I'm not sure who the main characters are as I haven't read the light novel. But they could be two young lovers who are facing challenges in their relationship.
The main theme might be about the complex nature of love. It could show that love alone doesn't solve all problems in relationships, perhaps exploring how other factors like communication, trust, and personal growth are also crucial.
The Twilight universe has such rich characters and a complex world. Fanfictions in this category can explore different aspects of the relationships and the story that the original might not have fully delved into, which is really appealing.