Who would you ruin it with spicy time?

Im "friends" with a guy. We both 33. We both worked together and was in our respective relationships. He became single and i helped him through the fallout of his relationship. I then became single but he was in a relationship. We were both single but only sent spicy dms and nudes. I got in a relationship. He got in another relationship. Fast track 5 years on. We both single. We just started speaking again. Spicy messages have happened. Do we ruin this fun fantasy thing we have or not? No, I will never be in romantic relationship with this guy. I enjoy the fantasy of it. So what would you do? Boy is fine as hell also.