Dead's Questions (2)

So i read a bl manga a while ago about two coworkers in an office who started to have sex with each other or something, i dont remember it that well. The top then stars neglecting the bottom and ignoring him, anand later on the bottom catches the top heading into a love hotel with another dude. So the bottom is heart broken and decides to move to another department in a different city. Once he's gone, the top realizes he actually loved the bottom and chases after him to reunite. Once there, they meet each other once again and the bottom ignores him, until he starts to realize that the top is getting sick from chasing after him, so he decides to get back together with him. Hopefully this is enough information, thank you for helping me !!

Aaaahhh, I accidentally closed all my tabs and lost the mangas I was reading, but I was really in love with this one, Idk the title but it was a Vamipire universe where they were called 'biters' and the bottom had brown hair and was investigation a case where a young woman had died due to a mysterious bite. His childhood friend, the top and also a bitter himself unbeknown to the bottom, told him to stop investigating. He doesnt, he gets attacked, his friend saves him, the bottom discovers the top is a vampire, and then they have sex. Hopefully that's enough info for someone to recognize it. Thanks in advance!