I'm looking for this manga about infidelity. I pretty much remember everything except the name. The Male mc and the female mc are already in a relationship and are out of highschool, the female works alot and gets tired of the Male mc's unwillingness to work. This is what makes her fall in love with her co worker( an old married man). I remember a scene where shes sitting next to him on a bench and she gets super horny from watching him type. To cut it a little short girl cheats, Male mc breaks up with her, story becomes more focused on Male mc after that, he gets his shit together. At the end they they both organize a meeting and hint at getting back together. Story ends.
Both have dark hair, artstyle isnt cutesy.
I think the name of the manga starts with G.
I know this is long as hell but I'd appreciate the help.

Remake thread without a useless poll

A just ruler amongst tyrants