He says he doesn't want to make Usagi worry but his lack of action makes everything worse. If he wants to make Usagi happy reject the dude flat out. The dude would give up if Misaki put more power behind his rejection instead of babbling, blushing, and staring wide-eyed. In a way Misaki is equally at fault for him not giving up.
Misaki has rejected him like 3 times and he knows usagi is his boyfriend. Sensei is just in denial.
Sensei! Don't waste your time on Misaki! You and Yuu can mend each other's broken hearts!
Yah but men are persistent, even after someone tells them no that doesn't mean they won't keep trying. I agree that Misaki really has to stand his ground and get it through that he doesn't like Sensei otherwise they'll just keep going in the same circle they've been going in and it's getting really annoying.
Thank goodness the cousins were there or that idiot Misaki would've went in circles again before just flat out turning whatshisface down. So damn annoying and he's 22 now.