I want to piggy back Puppy's comments a bit more here. TAM, what you need to do is validate H's comments without sharing what you are doing/going through. The key is to reflect back to H without getting pulled into H's drama/crazymaking talk. The below comments work as well:

"You seem....[insert thought/feeling]...."

"What I am hearing is......"

"Wow...that/this seems [insert adjective...etc]..."

"It does/doesn't sound [insert validating statement]....."

If your H rants or goes off the edge, a simple "I am sorry you feel this way" is the best way to defuse the situation.

Remember this is not about YOU. And I would strongly advise to stop even mentioning the OW or even acknowledge her in your convos. I looked past it whenever I talked with XW and she was flummoxed by it. Never once did I bring it up or even made a peep about it. And guess what XW never mentioned the OP to my face. grin This goes for all DBers as well.

The only time to talk about OW/OM/OP is if you are in the reconciliation phase.