Two scenarios came to mind immediately. 1. Merpeople. The MC is mermaid and LI's are all mermen, no need to turn it into a "the little mermaid" thing and bring in human LI's. Bonus, all the LI's are shirtless all the time. 2. A Coven. The MC is part of a longstanding coven and has grown up as a witch. Dating presents a dilemma because she can't let her potential partners know she's a witch until she can trust them, but it's hard to date someone when you're hiding being a witch.