Futari de Papa Hajimemashita
Shin and Yuuki used to be coworkers. Yuuki is gay and shin is straight, although shin falls inlove with Yuuki and gets rejected because yuuki wont be with someone who isn't gay. He moves to another country and returns after 2 years, when shin comes back he sees yuuki taking care of a child, his nephew. Yuuki became gaurdian and shin now helps him out with raising the kid. Shin tries everything to get together with yuuki and have the 3 of them become a family
Frontline Hazard
The uke and seme used to both live at the same orphanage, the seme (younger) was always inlove with the uke (older). They meet again years after in the army on the front lines of the ongoing war. The have a physical relationship and when the war ends they get together officially
Konya Kimi to Nemuritai
seme and uke had a sexual relationship. Uke was a prostitute and seme was his customer. They lost contact. 5 years later the seme still can't forget the uke and even still has a ring the uke previously owned. Seme enters a company and meets uke again as his coworker, but uke is different in appearance and also cold towards him. He finds out uke cant have sex anymore and wants nothing to do with seme. Heartbroken he plans to transfer away when uke confesses he actaully cant have sex with others because of seme, and that he loved him all along
Koinegau Horizonte