I'm annoyed at my friends for not telling me about my ex
Why wouldn't your friends tell you anything about your ex?
I think they were jealous of me and wanted to pay me back for making them feel bad through my actions.
It sounds like your friends don't think of you as their friend. In this case, you should communicate with them properly and confirm their intentions as you may be mis reading things.
I don't need to change how I see things or try to understand things. I know what I saw and felt.
Even so, your friend may not even be aware they upset you. It's fine to be upset with them, but at least confirm what they did was or wasn't malicious.