Best friend likes me

Now how in the fuck am i supposed to comfortably hang out with my best friend when he told me he has very strong feelings for me? He even asked me to tone it down with my boyfriend when he is around us because he can't handle it. I probably sound like a bitch right now but for months he has been acting like this and pushing his problems and mental health struggles onto other people rather than getting to the root of the problem in his head. We're going to a concert together in a few days and we've had this planned for awhile but im scared something might happen or we wont be able to enjoy ourselves fully. I dont even know how to handle this. I cant talk about my boyfriend with him, i cant talk about a lot of stuff with him actually because he gets all philosophical and says it's all pointless and he gets on my nerves so much i swear but we have class and a concert to go to and i am his support system for mental health but aghhhh im so sick of it all.