Even through that whole situation she was still pretty obedient about it. Her objections were definitely more on the "no means yes, kinda" variety. I predict the next chapter will be him too afraid to face her and her getting taken by someone else. Protag isn't worth anything in the first place so I don't really feel sorry for him. It's hentai so maybe there's a repeat performance where his insecurities gets the better of him, or another guy goes in for the kill, but by the end I definitely don't see them together.
"The early bird gets the worm", huh. Well, he isn't wrong, and I suppose him confessing to her because he didn't want her to be with other guys is as valid a reason as any.
But man, I don't know why he wants it kept a secret. He says he seems worried that she'll be disillusioned, but being able to talk things out is what makes a good couple, right?
Unless of course, rather than it being a lack of confidence, he really only confessed to her in the spur of the moment rather than because he actually liked her? He's a bit of a...What's the word...Loser? But I still want to see where this goes, so hopefully he bucks up, wipes his tears away, and start actually acting like her lover.
I'm guessing Moriguchi, on hearing the rumor mill regarding Matsushita, suddenly snapped and went all "leave his mark on her", hence the very rough sexy time that later took place. Now poor boy is majorly confused, possibly thinking he's put an impassible wedge between himself and his girlfriend. And it remains to be seen what she thought of it all, afterwards.
"Whoa ... That Is Deep!"
Well, I for one am ready for the continuation, when it comes.
I don't think there is a rumor mill it just seems the guy lost all confidence after hearing "all the guys will be gunning for her". So went the "I'll leave my mark on her" as you suggested and ran away. Honestly seems like a story where they will make up, but who knows as the title suggests otherwise.