Why this ex says I don't want him to be happy?

It is really annoying. My ex texted me that I don't want him to be happy and that I curse him that he will never be happy again. Well, it started yesterday, he texted me. So I replied with this " you know what something might happen in your life to make you cry and also go tru the same pain you brought into my life, I hope by that time you would realize how you hurt me"... so that was my message to him.me and my ex have had fights, been to ups and downs. I don't talk to him anymore but he said something yesterday that annoyed me. Why he would say that I don't want him to be happy when after all I've sacrifice just for him to be happy, he broke up with me. He gave up our 6 years relatioship for him to be happy. What more does he want. I've proven enough to let him realize all I wanted is his happiness. He is so inconsiderate to think that way