A swingers bar? The fact that she planned to go to a place like that with her ex doesn't make it sound like the healthiest relationship ever to me.
But man, what a guy! Our protagonist literally stepped in, told the guy to MOVE IT, and took what was rightfully his. RESPECT.
Great ending too. Ah, I really liked his cool response. Just going 'Hey, don't make me out to be just a dream' while lying naked next to her.
I guess I feel just a tiny bit bad for the other swinger couple? I mean, that's kind of what you go to an establishment like that for, right? But he really oughta learn to appreciate the lovely wife he has.
DAYUM! ... a story featuring young adults instead of high-school teens - Good Start, utu-sensei * Kurihara's apparent habit of inviting Naruo out for drinks whenever she and a partner break up ... put that together with the admission that they seem to quarrel at times and I infer someone has thus-far unexpressed feelings for the other * Swingers Club ... relatively safe in the H-Universe, not-so-much in real life (if-you-know-what-I-mean) * Couple who joined Naruo and Kurihara must be really into swinging; otherwise, no way in {_____} (insert name) would I personally swing my partner if she looked "like that" * Just before Kurihara gets busy with a stranger, something snaps in Naruo that makes him send a clear and un-mistakable signal to the swingers: "KURIHARA IS MINE!" ... and proceeds to (cough-cough) "relieve Kurihara's stress and sexual frustration, Like A Boss!" * The Morning After ... Kurihara regains composure, thinks it's all a dream ... Naruo breaks that illusion, splendidly.
In conclusion, I Don't Usually Ask for A Sequel, But ... THIS ONE IS WORTHY OF A SEQUEL. Make It So, utu-sensei. Do Not Hold Back ... It Is Your Destiny!