This is a yaoi manga. I don't really remember much about it. The main protagonist was very beautiful and he became the other main character's bodyguard. Mr. Beautiful Man (just going to call him that because it'll be confusing) was being persistently pursued by the other main character, but he is always rejected. Mr. Beautiful Man is only working as his bodyguard because the other main character said it HAD to be him. I don't remember what job he had been doing before, but I'm pretty sure he was still working for the same people, so it should have had something to do with fighting. I don't know if i am mistaking this for another manga (I don't think I am, but it's possible...) but the other main character didn't want Mr. Beautiful Man to get hurt (even though it was his job to guard him) so he prevented him from doing his job (i don't remember how) and got Mr. Beautiful Man mad because he thought he was useless.
Sooooo...what manga is this 😕

EDIT
I just remembered...Mr. Beautiful Man had light, wavy hair. I think the other guy had dark hair...

Is it Keep Out (KISARAGI Hirotaka)?

That's it!!!!! Thank you!!! 😀