So there is this guy at university who my best friend liked, but she had a falling out with him. He kind of knows that she had feelings for him, but he is definitely not interested in her and we all know it.
He has always liked me from the beginning and whilst maintaining a friendly relationship with him I always consistently avoided his expressions of interest in me, but a few weeks ago I realised that I have unintentionally grown fond of him. I am honestly a bit shocked at myself because I don't know how/when it happened.
He was recently really hurt by me because I became quite cold/distant in our conversations, and I think he thinks that I've been leading him on because I've been nice to him but suddenly turned cold. I acted that way because I was really stressed and just didn't know what to do about my sudden feelings for him when we cannot be together because my best friend is still trying to get over him.

However I really don't want to lose our friendship and I hate to have hurt him so much/created a misunderstanding. I am thinking about asking him whether we could talk and telling him that I am sorry about giving him mixed signals, that I do like him but I just can't go out with him because of various reasons (incl. my best friend), and whether we could just stay as friends? All I honestly want is for us to maintain a platonic relationship, and it feels like he will never understand or return to the way he used to be unless I give him an explanation. The problem is that clarifying this seems like the right thing to do when thinking about the hurt/confusion he went through because of me, but I'm worried that what I say will be disrespectful to my best friend because it will just sound like I'm putting the blame on her...
Thank you for any suggestions.