hi karennguyen,
You probably feel attached because he was your first relationship. That is perfectly normal. However, if he truly wanted to keep dating you, your “coldness” wouldn’t have kept him away. When a guy wants to be with a woman, he pursues her. If he’s “on and off”, then he’s not interested in commitment, he just wants some temporary company. I’d say you dodged a bullet, and it would do you well to heal and move on.
Of course that is the question, right? How to let go when you don’t feel like you can. I’d say call your friends, go do the activities that you usually enjoy, even if you can’t find the joy in them right now. Keep busy, distract yourself. Next thing you know you’ll be into what you’re doing and then you’ll realize you didn’t even think about him. It’ll get easier. Breakups are always hard at first. Don’t judge yourself for your feelings for him, just accept what they are and then focus on something else.
Good luck!
Patty