Novels about what it’s like to love someone who isn’t a good person

Hello! I (22F) recently have been doing a lot of reflecting on the topic of love and nature of relationships as one tends to do in their free time, and for some reason, I've found myself giving a lot of consideration to what I'd like to say is the "ugly" or "dark" side of loving someone. Some questions I've been pondering lately have been "Whether or not love can a conscious choice or decision?" and "Is true love always virtuous?" With that, these culminating thoughts have led to me wanting to read some literary fiction that captures the conflict of loving or falling in love with someone who isn't a good person (either in general or to them). I guess what I'm searching for is some novels that represent what love truly is to people and when love is not enough to stay in a relationship. I'm open to recommendations about romantic, platonic, or familial love and relationships. In addition, I'm also comfortable reading books with darker topics as well.

Let me know if you have any questions about my preferences or clarifications for what I'm looking for. I'm excited to see what's suggested! Thank you 🙂