Oh gosh, I have rtft and you need to talk to him about everything, absolutely everything. He is your husband, surely he ought to be the one person that you should be able to speak to about everything and anything?
How you have sat on this for so long is incomprehensible to me, this must be torturous for you.
For me, it doesn’t matter if he hasn’t spoken to her for three months or three minutes, just having her in his life has caused untold damage. You can’t unsee the words exchanged between them, which have eaten away at you for all this time.
I don’t know if you can repair this, you don’t know either, simply because it will take 100% effort and commitment from both of you. And it all rests on honesty, trust and a high level of quality communication.
It bothers me that communication is so difficult between you. I can’t help but feel that all this time you have focused on this thread could have been used to write to your husband, asking him all these questions. That would have been non-confrontational and would have started an honest dialogue between you. You could have had clarity by now, a plan, a sense of living and looking to the future.
Please do not underestimate the emotional stress you are putting yourself under, and the potential repercussions of this. Please take proactive steps towards a permanent resolution built on trust, honesty and clear communication. Good luck, OP