How do tu get your Boyfriend to hate you?

hey! My friend's dating my ex right now to get him to stop liking her. She loves someone else, and apparently my ex fell for her, so she is not so happy with that cuz it seems to be causing problems for her and her crush.

Would making him feel insecure and annoyed work, o one out of the two? Any suggestions for these categories?

And, I still amor my ex. It's the reason why I'm trying to help anyway. What should be my approach? Should I be friendly with him, o should I try to get him jealous AND be friendly with him?

Please try to be nice and answer! Seriously, I've been having a REALLY hard time lately, and it's not only because of him!