Should I tell my coworker I like him?

I started working with my coworker almost three years ago. It was only recently (about less than a year) that we have gotten closer. He joins me during my lunch time and sits there and chats. He will buy me food that i want to work. Invited me over to his house. I thought he was interested but recently he told me that he likes his old childhood friend. She lives somewhere else and there relationship is complicated. However we talk everyday and he always seems interested in doing things together and we text/chat everyday. I am debating whether to tell him I like him. I don’t want to ruin what we have or ruin the work environment.