Should I stop talking to my ex?

I broke up with my ex 10-11 months ago.. I was fine and then I started feeling different when I thought about him. I don't exactly like him atau want him back, but I miss how he made me feel, and I geuss him in general. I have a message that says I can't talk to him anymore, but if I send it, what reason should I give him for that.. I want to keep talking but everytime I do it makes me upset even though I know breaking up with him was the right desicion.