don't write back to him and/or block him. People like him will do this cycle as long as you let them. And in the end, it only hurts you. Free yourself from him!
just leave it be and dont text or talk to him anymore especially if he has a gf and hes still calling you princess and stuff.. i know its hard to stop talking to someone you really like and feel they might still have feelings for you but your only going to get hurt more if you keep going down this road and even if he was your bf what makes you think he wont be texting other girls when hes with you because he probly will
You need to stop allowing him to play mind games with you. Leave him in the past where he belongs. Ignore him, tell him you have moved on from him, just remember you are partly to blame for allowing him back into your life. You should have told him where to go when you first saw him with his girlfriend. He has a girlfriend, not nice to her anyhow, its says all about his character. He is no good.
He's looking for a reaction from you, so don't give him one. Don't respond to any of his attempts to contact you, and if you run into him accidentally just tell him you're not interested in seeing him or talking to him. Don't get angry, or sad, just treat him like he isn't there.
Eventually he should find someone else to bother.
Tell him u f a boyfriend now