Since his method of communication is texting, then I would text him. Just be honest and state that you have given the situation a lot of thought and you realize that the two of you have very little in common and you wish him all the best. You don't need to go into an elaborate excuse. Keep it short and simple. Don't wait until Thursday to do this. It's better to end it quickly.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
