Basically novels where the initial love interest is with a guy that's against or at least in conflict with the MC. The MC gets stronger and either ignores the girl or takes them. I know neither Ankoku Kishi and Revenge of the Soul Eater has gotten past that point but that's precisely why I'm looking for a novel that has.
Magi - both animes and the Sinbad prequel did a fantastic job of bringing it to screen and the manga is complete. As to how it relates to your request, the love interest is initially with an enemy and switches sides after a while. And MCs get stronger too.
Magi is actually a trio of protags with 2 of the 3 ending up married at the end of the manga (Alibaba and Morgiana). Edit:to clarify they marry each other. And watching the prequel isn't needed at all for following the main series.