My best friend and ex became a couple?

[lurilu]

Okay so this ex cheated on me that's why we broke up, me and my best friend were totally mad at him that time but when my best friend broke up with his boyfriend, they started to be close with each other. I was my ex's first gf and he was totally inexperienced and don't know how to handle girls, I always have to make the first move and it pisses me off all the time, he wasn't sweet at all. So my best friend asked a permission if it's okay for me if they become a couple then I said okay because I already move on. But now it hurt my pride all seeing them lovey dovey on Facebook all the time and there is always a group message that my best friend was sending to many people including me about their date, how they love each other and so on. It just pisses me off how my ex are doing all of the things that I want him to do to my best friend when we were a couple. It feels so unfair, I feel like he wants me to regret breaking up with him. It sucks. Is it okay to feel like this? I really feels like a bad friend.