HELP ME PLEASE!!!

Please help me! I'm in tình yêu with my neighbour but he already has a girlfriend and he loves her to bits. I'm absolutely crushed! I really, really want to tell him how I feel but I'm terrified at the same time because of his girlfriend. I mean, what would she think if she found out? And what would he think? I think he's starting to get suspicious because nowadays he spends all his time with his girlfriend and he's literally ditched all his old Những người bạn and when I tried to speak to him about it he said, Why do bạn care? And he wouldn't stop bugging me about it. I think he know's that something's going on. What if he realizes that I'm in tình yêu with him? How will he react? I mean, yeah, we're good friends, but I honestly haven't got a clue how he'd react all the same. Half of me wants him to know but the other half is scared stiff. What should I do? I'll give các điểm thưởng to anyone who can help me.