Ex is now engaged - apparently, karma doesn't exist?

Now, before any judgments about my character, I am not a vindictive and venomous person. But I had a relationship with a guy who later turned out to burn me deeply emotionally. He was mean, toxic, hurtful, and just a downright douche with no respect for me even as a human being. The things I went through with him are too much to list here, and I can honestly say that it changed me as a person, in various ways, some of those ways being worse off. I am finally over him romantically and emotionally, but he seemed to have hit the jackpot recently - he just got engaged to a really worthy girl. She is beautiful, sweet, caring, church-going, and family-oriented. I know her, and she is a wonderful person. Makes you wonder why a girl like her would go for a guy like my ex. Back in my period of heartbreak over my ex, I always tried to console myself with the thought of him "getting his" in the future - I thought to myself that surely, you can't leave this earth causing as much pain as he caused to me, without feeling the repercussion of it in some karmic way. But .. I seem to have been wrong. He has struck gold, he really has. So my question to you guys is, do you believe that karma exists?

As a side note - when he had been dating her for around 2 months, he tried to sleep with me! A real winner here.

Even though I am over him romantically, I am still upset about the fact that he told people who we're acquainted with, that we had sex (we never did). How would you save face? I'm a virgin and I can't stand people thinking that we had sexual relations ... it's disgusting.