Chapter 3 is a very loveable and refreshing story with lots of humor, by Miyoshi Maki:
http://www.mangago.zone/read-manga/kanpeki_kareshi_kanojo/
You can read the rest there!
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I really liked this manga at first! But Hayata's personality changed so much from the beginning because of the unnecessary misunderstandings! I love drama! But this is ridiculous!
The poor guy is insecure; he is younger and he felt that he was not there to protect her while her ex was there to help. If everyone is so wise and able to solve problems without misunderstanding right away, then a lot of these situation in romance mangas wouldn't be possible right; the story will end much faster too.
I am not questioning the drama, the story. I am just saying this is too much (unnecessary) for a teenager story. While they were so natural in the beginning, they are like the three main characters from the movie House of Flying Daggers now.
Maybe if they were a bit older, the drama would be more genuine.
Do you call this "Attacking little by little"? This was going in full force!