Help! SOS

I had sex with my best friend yesterday we both were really drunk and he told he'd loved me from a long time ago, the problem is I like someone else and my best friend already asked me out, I love the way he is with me and because he respects me and accepts me for the way I am but im not sure dating would be the best thing for both of us. What should I do? Yesterday he told you'll regret this I know it, and I was saying that I wasnt but honestly I don't even know if I am.