I'd think confronting your W as to someone else's actions that are out of her control is unproductive. Expecting her to be able to answer the question of why OM won't respect her wishes is not a question she's in a position to answer. If she's made that wish known to the OM, maybe.... you could call him and calmly and concisely tell him to respect that wish? Or change your number.

Has she made a formal request to OM that he no longer contact her? When my ex did, after her EA was discovered and she decided to work things out with me, I later was told by a third party that he went ballistic and tried every which way to contact her. It's probably normal for these goons to try and retrieve what they've just lost.

BTW, the thought that also occurs to me is that when we see the OP disrespecting the WAS's request, it says a lot about how frickin' selfish and unconsidering of the expressed wants and wishes of the WAS the OP really is deep down inside when push comes to shove, doesn't it?