Should I stand up for myself?

So, as some of you know from reading my posts, I work with my Narc. This makes no contact difficult, especially when there are work-related social gatherings that I either have to just never participate in, or go but risk some kind of painful situation with the Narc (because he will ALWAYS be there.)

Last night was a going away party for 2 people at my work, and I decided I wasn't going to let N scare me away from going. So I went, and he ignored me the entire time, did not come over to speak to me or say hello even once, even though earlier he messaged me "see you down there." Sorry, but this hurts. Because just a couple days prior he was acting all charming and flirty and intimate with me, just like old times. But as soon as other people are around, it's back to acting like I don't exist.

So, fine, I act like I dont care. Except once I excuse myself to the restroom, and sit on the floor and cry for a few minutes. But I cleaned myself up and went back to the party.

Well finally we end up at the same table with several other friends, and finally he's like "Oh hi" as if he just noticed I was there. I coolly smile and wave, go on talking to my friends.

So at one point the N is ribbing his friend for having a credit card with his/his wife's pictures on it. I say, I think it's nice.

Later the conversation at the table is about birthstones. You know, which one goes with which month. Midsentence, N says something to his buddy about my birthstone being amethyst. The new guy at work interjects "wow, you know what her birthstone is?? That's just as bad as that guy's credit card." In other words, wow you must really have it bad for this girl to know her birthstone.

Now this was a totally innocent comment on new guy's part, but really awkward and embarassing for N because the fact that he and I were together is (he thinks) a secret. Because he was engaged at the time. And now, against my wishes, he is married to that same woman. This has been the cause of so much pain and arguing and tears and just horribleness for the past year +.

So N is basically caught with his pants down by this comment, and decides to save face by throwing me under the bus. He turns to his buddy and scoffs, and says "No, I'm more into the Aries actually" (which I assume is his wife's sign). In other words, he wanted EVERYONE TO HEAR that I was nothing to him, and he would never be remotely interested in me b/c what he has is MUCH BETTER.

Only problem is, I was sitting right there as he said this cruel and humiliating thing. Me, who he used to say was his soul mate and his star-crossed lover and his special little this and that and one of the most beautiful and wonderful women he had ever known. Me, whose heart he shattered in a million pieces when he went to the altar and never even TOLD his fiancee about us. Me, who ended up in therapy because of him. And to cover his own ass, he decides to add insult to injury and cut me down to his friends.

SO, SO, HURT. Even though I know he's an asshole. My God I didn't even think he could be that cruel and horrible. And now, I really want to confront him and tell him, hey I heard that and it really hurt me. That was cruel and horrible and I don't deserve to be treated like that.

I feel like if I don't say this to him, it will continue to bother me and fester. And I will be mad at myself for not standing up to him. But on the other hand, I know that if I do confront him, he will try all the N tricks to make it my fault, turn it around on me, and just hurt me more. What should I do?