Akhems I suspect you would agree however that you cannot even begin to move on and decide to "stay" with someone while the other relationship is still ongoing.
RBJ lots of affairs are like fantasies and it is the secrecy and illicit nature of them that serve to fuel the intense feelings. For some people, even after their partner has discovered the affair, it is still not enough to burst the bubble and end the relationship.
This is why you must not collude with him in keeping this a secret from the wider world. If he hasn't made a definite decision by now to end things with OW and sever all contact, there are some very definite things you can do to hasten this process - and also give you back some self-esteem.
You start confiding in RL people, including your in-laws. You ask him to give you space and move out. If he wants to see his DD, you facilitate contact with boundaries, but you don't take that on as your responsibility; it is his. In all these actions, you take back your control.
Very often, once an affair becomes public knowledge to people like his work colleagues (given what you've said about his camera, they know anyway) his family and his friends and he faces the reality of having to sleep on a mate's floor, the shine of the affair partner wears off pretty rapidly.
If the OW has her own place, perhaps you fear that if you ask him to leave, he will go to live with her? Well, this is one of those situations where you will have to risk that happening, but again this tends to hasten an affair's end, when one or both of them realise that they aren't God and they do their washing and fill rubbish bins like the rest of us.
In doing all this, you take back your control and hasten resolution, one way or another.
Now, this is going to be difficult to do if you're not getting support from people in RL, which is why I'd urge you to talk to someone who has your best interests at heart. Avoid anyone who sees it as a competition between you and the OW and friends who feel that women should just suck up whatever is thrown at them, "for the sake of the children" should be avoided too.
That phone counselling session would be good (today, if possible?) but in finding a counsellor generally, the two questions I would ask in screening for one would be: "What experience do you have of helping individuals/ couples deal with infidelity?" and "Have you read Not Just Friends? and if so, what is your view of it?"
Please don't be passive - and when you get that book, the first things Shirley Glass (and indeed any author on infidelity) says must happen is that the affair is ended and contact with the affair partner, severed.