breaking up in manga?!

i already have this question in mind for a while now since i often see in Mangas that there are characters who just broke up with there gf/bf and immediately go out with the next.
i mean when i break up with someone i need a break first and dont jump right on the next target. especially if i really liked that person.
so i was wondering is that such a japenese thing (or just in manga) or am i the odd one?