If you start making moves to break them up, it will be way too easy for them to paint you as the bad guy, or a crazy bitch. They will bond over it, and it will likely have the opposite of the intended effect. Your trying to break them up will turn into the glue that is holding them together.
Many OW and WH's have this "us against the world" and "our bullshit lurrrve is worth sacrificing everything for" dramatic mentality that your efforts will only reinforce.
If you have some hard proof that he is cheating on her, or something like that, that is one thing-- you could always send it to her, anonymously, and let the chips falls where they may.
But, if you have to manufacture scenarios that may or may not lead to the demise of their relationship, it will probably come back to bite you in the end. You could end up with a restraining order slapped on you, which would be a fresh humiliation that you simply don't need.
Revenge fantasies are normal. But normal isn't always healthy. If you can, take the focus of them and their shitty, adulterous relationship, and focus on you and the new, bullshit free life that awaits.
Don't worry about hurting OW. In time, your WH will probably take care of that all by himself.
As strongbutbroken says 'DON'T PET THE DRAMA LLAMA".
Turn it around. Put that focus on yourself. That's an investment that will yield REAL returns.
"Keep your face always toward the sunshine - and shadows will fall behind you."
The OW didn't hurt you, she owned you nothing...your ex is the one that broke the vow to you. Focusing on her will do nothing for you. Let them have each other, they deserve each other...a cheater and someone who thinks cheating is a good idea. Let them have each other.
I would suggest you get into therapy if you haven't already. You have to find a way to stop obsessing about him and work on healing your self. Take that energy and create a new life for yourself.
Time to let go.
We have all had the fantasy of something happening to break up the WS and the AP. That is perfectly normal. However, you must get past that and start building your own life. I know my response to the OW was if he will cheat with you, he will cheat on you.
Most of these fairytale infidelity relationships end on their own because basically they are built on lies. Eventually real life sinks in and they discover that it doesn't make them happy afterall. I am sure that some hang on to the relationship so that they don't look like the fool they are, but most don't make it.
Please try and get to a place that you can let go. You don't want him back so don't dewell on what he is doing with who. It is no longer your concern. The karma bus will catch up with both of them eventually. Just concentrate on taking care of you now. (((HUGS)))
Here's the thing, what if your successful, and he doesn't come back to you? Then that hurts too. What if they get back together? And back together, and back together again after that. It's better to turn your focus away from them and focus on you.
Keep posting on here. It's a healthy step in moving forward.
If it wasn't this OW it would have been another. I find the OW an affront to the sisterhood but I don't blame them for my husband betraying his vows to me.
He was a Wayward long before he actually cheated. It has nothing to do with the BS, nothing to do with the AP, it is ALL about the fucked-up coping mechanism of the WS.