I have been happy with my life now but not until he came back and created chaos in my mind again. It feels like a ghost from the past made its way back to me. I was lying on my bed while scrolling my phone up and down out of boredom when I received a text message from him; he was asking me how I’ve been. Why does he has to come back? I was doing fine without him. I was bringing out the best in me. I have been enjoying my life--- going to dream tours for singles and having staycations. I think I have finally forgotten him but he ruined it.

Where does he live? He is local? If not, then you could probably just block him and move on!

I feel you. It's just the matter of whether you'll allow him into your life again and do something in your life that you'll regret, or it could be the other way around. If  you don't have any feelings left for him anymore, then there's no reason to respond. If he's bugging you, then tell him to stop. Don't let yourself become so bored so you can get your eyes off your phone. Get out and have some fun time! I'm pretty sure you'll find more interesting activities that's worth your time.

Now if you still like him, and you think there would be a second chance, then let him in. There's nothing wrong with that. But make sure you're emotionally prepared for this situation and whatever comes after, you get out of it without hurting yourself.