Wait wat he dated sena? But in the past wasn't he dating the art guy? And who was dat one ...

I believe they are different but i'm not 100% sure...but I think the translation was incorrect and the art student's name is Natsumi not Natsuki.

They are the same, There's no error in the translation. The looks, the attitude match. And the friend in high school that teases natsuki, is the one who Sena is dating. Here's the theory I created simply to put my mind at ease (there's no facts, i made it up): The art dude was cheating, he was going to marry the girl however he didn't want to leave natsuki (due to what he said "marriage is for show, for the family and for the women... but I won't aprove of you marrying natsuki"), Natsuki understood and dumped him, years later he dates sena but he is pratically a brat, dumped sena, then enters the friend of high school.. Sena and Ma-something date, and natsuki is currently single LOOL This is how I move on ahah

Same guy

The manga is presented in chronological order:
1. Sena hits on co-worker, co-worker returns with ex.
2. Sena and Natsuki are breaking up. Natsuki is a highschooler as seen in the photo (uniform/ch 2 p 10) and it is implied by Sena: "I thought... adult love was easier" (ch 3 p 17), while refering to Masayuki in contrast with Natsuki.
3. Sena and Masayuki become lovers.
4. Natsuki and Ichikawa involve with each other while Natsuki is a highschooler.
5. Natsuki is now working and living with Ichikawa. He is insecure and it doesn't help to see that woman. Ichikawa rejects the [his/Ichikawa's] idea of marriage, telling Natsuki is more for show off, so he apologizes for not being able to "say it properly" (ch 5 p 32). But, he loves Natsuki and it ends with them making love and wanting everything of each other.
6. A grown-up Natsuki (in a relationship with Ichikawa) meets up with Sena and Masayuki. Time has passed since ch 2, because Sena thinks to himself: "He's [Natsuki's] grown cute".

So, it ends up with happy endings for everyone! :)

Ok, that means Sena is a SEKE?? He gone from seme to UKE ????

More and more mangaka are writing gay characters realistically in their bedroom habits. In real life, most gay men switch positions, often in the same love making session. There are "exclusive tops" and "exclusive bottoms", but they are the exception and not the rule. (My brother is an exclusive bottom) The idea of characters being exclusive ukes or semes was a writing device to help the audience, predominantly women, identify with the characters. Since a woman can never "top" her man, having a seke character was thought to alienate the primary audience. Now, however, realism has become a fetish in it's own right within the Yaoi genre.