Hallo Although there is a line of MNers wanting to kick your husband in the balls I think many of us can equally understand that you are not a "confrontation" person. And that you want to keep your marriage.
But you can feel justifiable anger at how he has behaved without shouting at him.
And you can be assertive without being confrontational.
And you need to get your marriage into a place where it's worth keeping and is stable enough to withstand the next difficulty that life throws at one or both of you.
In very different ways, and with different strategies I think everyone is saying the same thing.
You need to ensure that there is to be no more contact with the OW. Whoever instigates it. She can be as persistent as she likes but there are ways to stop it as long as your H cooperates fully. He needs to work with you to give you the proof that you need that this is the case.
You need to ensure that your H knows that he has acted very, very badly and is at risk of losing you and the DC if he doesn't wake up to this fact and put his all into repairing the damage that he has caused.
You need to communicate. As much talk as you need. On your terms. At your instigation. Perhaps also with a counseller?
If necessary, would you consider writing him a letter to lay out some of your feelings and requirements?
Again, take care of yourself. You've done nothing wrong.