Have u read Overdose?
Warui yume.
Higouhou Junai
The seme unconsciously hurts the uke by being nice to him after rejecting him. Furthermore, he is really nice to his colleague who is also in love with him. He gets a taste of his own medicine and regrets his actions after the uke gets together with an ex, who he was forced to break up with after their parents found out.
Aishuu
Hehe....hehe...hehehe...did you read the question though?
Thank you everyone guys!!! I've just finished reading all your suggestions and they're all good!!! ლ(´ڡ`ლ) Now, I want more!!!
I just can't get enough of the the one who was hurt having the last laugh!
I'm looking for mangas like Hina wa Mitsuiro no Koi ni Torawareru where one of the the seme (or uke) got a taste of their own medicine of playing with their lover's feelings. It doesn't really matter whether he was forgiven of not, I just want to see them regretting what they did. ╮(￣▽￣)╭