AITJ for hating my best friend boyfriend?

My best friend is like a sister to me. I know about the terrible experiences she's had with her partners, and I've always been there for her.
She currently has a boyfriend. At first, I simply didn't care, until her boyfriend started being insecure. For context, I'm a genderfluid person with a strong attraction to men, and the guy was convinced my friend was cheating on him with me, even though both of us were more than disgusted by the idea. In the end, because we were fed up with his insecurity and because my friend's mother and mother-in-law supported it, we told the biggest lie:
I pretended to have a twin sister, a new name, and that my friend had "blocked" me. Although her boyfriend stopped being so insecure, I currently detest him. I find it hard not to get angry when I hear his name, and honestly, I want them to break up. So, am I the jerk?