The uke said that he never had a boyfriend, so I believe you are right!
Dude it is one of the scariest things especially in real life. I had it happen to me and boy was I confused when after not speaking to them for like 3 months they thought we were dating and that we had a conversation that we were. Like "no that never happened" and now I'm leaving. Some people are really delusional that it's terrifying when they just don't leave you alone after explaining such things to them. It's the weirdest thing so I immediately thought that when the hasagawa said he had been dating him even though the uke was known to just mess around I was like tf?! But yea crazy people out there. (ó﹏ò｡)
I wonder if the guy who hired him only had an illusion of dating our other main. After all I have not only seen that, but experienced it where people end up under the illusion that you and they are dating even if you have never even had a conversation with them.