I don’t think we can blame him, ML really put him through a wringer. Years of crossing boundaries and pretty much harassing a guy who just wants to move on and doing that while he still had a beautiful bombshell finance. Confessing doesn’t just erase the past, MC is still very insecure and hurt from years of unrequited love. He gave up long ago on the possibility of there being a romantic relationship, excuse him for not being confident and romantic lol

The MC annoys me, not enough to stop reading but enough to make a comment. The MC wants the benefits of the relationship without taking on the vulnerability or risk of actually committing.
The ML has done all the heavy lifting: he broke up with his fiancée when confronted, ran to the MC’s hotel room to kiss him, and consistently takes the lead on every date in recent chapters. He’s clearly fully invested in making this work.
Meanwhile, the MC refuses to take any initiative. Even after the ex-fiancée spelled it out and told him he had a real chance, he still wouldn't confess. Between his fear of vulnerability and what I believe is a bit of a superiority complex when it comes to his feelings in the dynamic of the twos relationship, he stays on the fence and looks ready to bolt the second things get difficult.
I saw the comment below mine call the MC insufferable, and honestly, I have to agree.