I know you are hurting so please consider what I am saying. I've read more than one of your posts and there seems to be a pattern that this person replied to you sometimes but not all the time. You had an agreement and he broke it and probably is now avoiding the responsibility and not replying to you even though he knows you are hurting. This is not good. This man is not worthy of you for whatever reason.
He could have mental issues, he could be playing mind games, or he could be just plain evil. Either way, you are the one who is devastated in the end. I understand, I had a friend on the internet or so I thought and he was like that in that he would often not reply back for whatever reason.
If you really loved someone would you treat them in this way? People show who they really are by their actions. The internet makes it so easy for people to play games and hurt others. It is so easy to type a few words but what is really behind all of this? Bad people use the internet because it is easy to ignore you and disappear since it is online and not in real life. I personally don't have a high opinion of relationships over the internet because of this. Social media is full of people who are self-absorbed attention-seekers and/or disturbed people wanting to hurt others and play games.
I know it's hard but you need to ask God to help you overcome this and don't go after this guy because you will only get hurt some more. Let God deal with him. Let God reveal to you who he really is. You deserve better than this and don't just give your heart too easily to anyone, especially on the internet.