i miss somebody who was never even mine

i connected with somebody off of reddit sometime back. we clicked instantly and amazingly well, very rarely i find somebody who i click with this good. we started talking and would talk all night and alot during the day. he would mention serious things about the future etc. after around 10 days, i discovered he has a girlfriend who he has been in a relatioship with for a year. my heart broke. i confronted him and removed him, but im not able to stop thinking about this. just wanted to share this, nothing else.