Okay, after some imagining about a dragon doing it with a human, to make it less weird she did say "your promise to make me your wife". Here we can assume that he, as a dragon, is sentient, intelligent, and can talk like human do.
So, it's more like human x elf rather than human x horse, dog, cat, or other non-speaking companion.
Can someone please explain me why do you hate dragons so badly that you made a dragon main character not being a dragon anymore?!
Stop hate dragons, damn it!