I told my ex I didn’t want to be in contact for a while after the break up because he was sending mixed message texts and I needed time to get over things. He said he’d be there when I was ready to talk and that he loved me. I contacted him after 3 weeks and he hasn’t responded after three days. Is this because he’s already moved on?
This is kind if odd… please don’t panick, your ex might need some time to also deal with the break up and gain some perspective. Give it a little time, wait for them to reply and I guess if that doesn’t happen you know where you stand. Be patient. Good luck!
Farax next time don’t announce the NC. Just do it. Anyways he is ignoring you on purpose. Im sure he hasn’t moved on. 3 weeks is too short. You don’t want him to miss you, you also want him to change. In 3 weeks no one can change. Give it more time. He will reach out. Goodluck!
Thanks for your responses so far 
It’s been a week since I messaged him and no response.
Is it possible he’s angry/surprised I didn’t contact him for so long or has he realised he no longer cares about me at all?
Perhaps he didn’t mean it when he said he would be here when I was ready to talk and was just trying to get rid of me
You have the right not to talk to an ex for any time you want. If he got mad and its taking revenge on you then its on him. Its hes fault you guys are not talking. Don’t mind him he hasn’t moved on. Men take way longer than women to realize they miss someone alot. You were right to start No contact, that way you won’t help him move on. I wish you the best.