Okusama wa Mahou Shoujo, Shugo Chara! Recommendations
Main characters of these series are both magic users who will lose their powers in the future.
Amu, from Shugo Chara, will lose her powers once she grows up.
Ureshiko, from Okusama wa Mahou Shoujo, will lose her powers once she kisses a man.
Both are mostly comedies with a bit of romance...