I'm actually a little confused here. First he friendzoned Narita, then tried to break up with Yuuko (which didn't work) then he landed up at Narita's house who ended up letting him in anyway? Or was there some sort of timeskip/flashback?
He probably feels at ease with Narita, the same way he felt with that Senpai in his backstory chapter so he probably can't commit 100% to anything. Atleast thats what I believe.