And maybe you need to be kicked in the head.
You don't need to fuck a bunch of strangers. How is that going to help you? Will it make you feel better to "hurt" your wife the way she hurt you? What if she doesn't care? Now who's the one hurting himself?
Sorry to be so blunt; I know you're hurting. We have made many startling discoveries since we started swinging, and one of the biggest shockers was that all the fears and hurts and pains we experience are of our own making. I don't know if it's "insecurity" per se. It's more about what you choose to believe. If you interpret your wife screwing the bejesus out of some other guy as a horrible thing, then guess what? It is. You are free to interpret your reality however you want. I don't think I can explain it but it's sort of a matter of taking your head out of the emotion and looking at things objectively. If emotion had nothing to do with it, would it look any different to you?
Now that said, I'm not exactly applauding your wife's callousness. Excessive drinking is never a good idea in a situation like that, even when your rules aren't so stringent. Because as EvilMJ said, it's like your Get Out of Jail Free card. I read a post once about a swinger couple who went to a "vanilla" party where the "cups were overflowing", and there was a whole lotta fuckin' goin' on. Oh, but they weren't swingers. No no, they "weren't themselves" that night, and it was the alcohol that made them do such bad, bad things. Let's never speak of it again...until the next party.
Bottom line: you had a set of rules, and your wife violated them. Period. Whether she thinks it's a big deal or not is irrelevant! What matters is she HURT you! YOU think it's a big deal, and that should be a good enough reason for her to NOT DO IT!
No more swinging for you! (saith the Sex Nazi). If she can't follow rules, she can't be trusted. You can't swing with someone you don't trust. She's got her work cut out for her rebuilding that lost trust. For now, stand your ground and the next time she tells you it wasn't a big deal, you tell her that it IS a big deal to YOU, and she needs to respect that.