I don't think he was considering dating you - instead I think he was reacting to something you'd said and was making a negative comment. Kind of like when someone mentions chucking a lot of sickies and a friend says "remind me not to employ you". Or if someone mentions trashing a holiday house and is told "remind me not to rent my house to you"
What did you say/do before he said this?
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.