I don't have one. But I admittedly don't believe that what goes around comes around---at least in this lifetime. I've seen far too many people skate through life, behaving egregiously, with no consequence at all.
My ex is living in much-reduced circumstances. He is very, very ill. This isn't karma. The reduced circumstances are a natural consequence of spreading the same amount of money across two households. (My circumstances are reduced, too, thanks to choices he and OW made for me.) And he'd be sick no matter what--and, in fact, was very ill for many years prior to his idiocy. He was impotent before, too. There's no karma here--there's just the culmination of a lifetime of really foolish choices.
As far as I know, OW's life remains "karma"-free, too.
Kansas, my jaw dropped when I read your story of "karma." I have to admit it made me very sad that you're reveling in the OW's husband's heart attack, job loss, and loss of benefits. Not just sad for him, but for you---sad that your husband's infidelity took you to a place where you would find another BS's pain positive in any way.
What really happened to "your" OW when this "karma bus" hit? Nothing. She is left in the position occupied by every responsible adult human on the planet. She needs to revise her unrealistic dreams. She needs to work hard rather than exploit others. In essence, she has to grow up. This isn't karma; it's life.
By all means, revel in what befalls OW, if it makes you feel better to think of her in the "ucky" part of town--fine.
But what you've primarily described are the tragic consequences that arose as a result of egregious harm to the other BS. It's very likely that the suspicion of--and later, confirmation of---his wife's infidelity with your husband contributed to both his job loss and heart attack.
How does that represent the karma bus visiting OW? Or--more pointedly, the man with whom she worked to destroy her marriage and husband (because if you're going to go the karma bus route, you have to recognize that real justice involves all concerned)? She may have experienced the fallout of her husband's dire misfortune, but is again left in victim mode; she has no need to own her actions.
More importantly (and tragically), it leaves you--a BS--celebrating the enormous misfortune of a man made BS by your husband and his OW's choices. Does that strike you to be wrong in any way? Does it really feel like karmic justice has been meted out?
I'm not trying to be bitchy--I'm trying to point out, if what goes around comes around (and again, I don't believe it does, so I'm really just playing Devil's advocate), we need to be pretty careful about how we choose to rejoice--because it might place us in the middle of the road when the bus is coming.