I struggled to read it all the way to the end. The plot is basically cyclical- someone wants to break them up, assaults the girl, they overcome it, and then it all repeats.
If you like smut, there's plenty of it, and if you like the typical shojo couple then that's there too. But beyond that... the suspension of disbelief for the sake of smut is a little too much. Can you buy that a girl who it supposedly great at karate would only wait to be saved by her boyfriend each time she's sexually assaulted? Can you believe that a girl would be assaulted multiple times by five different people in less than a year? That two teachers would independently be trying to break up the couple?
Beyond that, the characters border on irritating. As I said, the girl seems to magically forget her karate training and act like she's completely helpless without her boyfriend. And again, the story seems to be constantly repeating itself which can only hold your attention for so long.