> I didn't want to be too flirty as we live a thousand miles apart,
Which means you didn't want to show interest in him.
> also I haven't been bombarding him with messages, he would always text first.
Which means you're not showing interest as far as he's concerned. Men don't want to have to do all the work. It's clear you are not interested.
> I didn't message him since,
Which is showing you're not interested.
> I really don't want to make a fool of myself,
Which means you don't want to have clear communication, or take a risk of getting hurt. Men don't like that type of girl. They avoid them like the plague.
> I cannot find a way to explain this, I did not say anything mean or anything that could scare him off.
Incorrect. You scared him off by not showing interest. You ignored him, didn't initiate conversations much, and it was very clear you just couldn't care less about him. Stop taking bad advice from supermarket magazines, and "life coaches" who don't know a thing about relationships. Say what you mean, mean what you say, and initiate at least half the conversations.
If you can't have good clear conversation, you will not keep the good guys, you will find plenty of bad guys though. They have lower standards.
I have a long time interest in psychology, specializing in relationship dynamics for 30 years.
(Please note, we give the best advice we can based on the information given in a post. For better advice, please include the age of all romantic partners.)