Yes, we all know that in real life MMC would be basically a psycho (changing appearances to look like Miki's ex, going to her house on the freaking second day and making breakfast for her, and willing to change schools because he thought Miki was dumping him -at least he is somewhat self-aware that what he is doing isn't normal), but this is a manga and is written as a fluffy rom-com, enjoy it as it is.