Really? I didn't think he was that bad at all. He never really does anything bad? The description makes it sound like he's threatening her but he isn't, really. He says several times that he won't tell anyone and that she should trust him, but she refuses and keeps making him lunches because it's the only way for her to feel secure. He was kind of clingy and annoying (though I found that cute) but in the end it just boils down to him being a lonely but nice boy.
Even his "playboy" aspects weren't really real. He flirts back at people who flirt with him, but that's about it. It doesn't go beyond lip service. I really don't think he was particularly scummy at all.
In the end, this is a pretty cute manga, in my opinion. The ending wasn't 100% satisfying, but it was the best ending possible in the three chapters they had.