Am I wrong for being happy my sister is miserable?

My sister had an affair with my ex-husband and told me to my face that I was just jealous that I wasn't doing what I needed to do to keep a man and how she knew how to keep a man. We divorced and then they ended up married and she rubbed that shit in my face. Then when she got pregnant she rubbed that in my face because I can't have kids. It's now been 5 years and I'm dating an amazing guy. He's an extremely selfless lover and such a wonderful guy. When we first started dating my sister was going around talking about me because my boyfriend is deaf and just making fun of him.

However, whenever we would see them at family functions she looked more and more miserable and they argued all the time. Then I started talking to my sister's ex-best friend and she told me all the tea. She's walked in on him cheating on her several times. He also never goes down on her which was a problem in our marriage. I'm not saying men can't have boundaries but he honestly didn't care if you got off or not. He expected you to give him oral but not vice versa. Just the opposite of my boyfriend. Turns out I didn't know what an orgasm was until I got with my boyfriend.

I'm happy and my sister is just fake smiling like "I won in life I swear!" And her eye is just twitching. I don't wish bad for anybody. I don't like negative energy out there. But there's something about karma that I find delicious.