How do u tell my best friend I'm falling for him?

I've been best friends with this guy since we were 16, we are now 33. We've both had several serious relationships throughout the years. We are both currently single. We live in different cities, but he's planning on moving to my city next month for work. We went in a trip about a month ago to meet in the middle and had sex/ I recently visited him for 2 weeks, stayed with him and had sex again. We went out a lone and went out with his friends while I was there. We've never talked about dating or our feelings. Being a girl, with all the above, of course I'm falling for him. How do I tell him?! HELP!!! He's the one who initiated every phone call and or text everyday and the one who invited me to stay with him etc.

Thread already exists, (below).