I'm so sorry, OP. That is a heavy load.
I am picking my way through a variation of this, although not quite as all-encompassingly deceitful, 'just' a regular affair disclosure. @Natty13 is wise; please play the long game. Do not risk future hardship because you were too wrong-footed and caught up in the moment to do due diligence on your potential outcomes. It sounds unfeeling and cold, but now is the time to 'love yourself more' and plan ahead.
You do not owe your husband any kind of closure or reflection-time; he afforded you no such luxuries. Presumably he now knows you know -OW must have told him she's been in touch with you? If he knows you know, how is he acting? If not -great! The greatest gift you can give yourself now is time: time to process your feelings on your own without someone else trying to influence you, and time to get your head around what a future having gone your separate ways might look like. Not to 'fuck him over' necessarily, as Natty13 says, but to make sure you're acting in your own best interests.
Since his disclosure, we have had some very honest conversations and re-evaluated what our relationship is now. He's stopped contact with OW and is very remorseful, trying to make amends. I have, after much soul-searching, decided that it is now my turn to be a bit under-cover (he's had his turn), so I am sort of reverse-affairing him: stealthily walking backwards toward the door without him noticing. I am going along with his efforts at trying to fix the mess he put us in. I'm not pretending to be over it -I am being honest about how much it still hurts and that it's changed how I feel about him- but I have not told him that I've already made up my mind that it's over. This is because, knowing him, I know that getting my ducks in a row and leaving will be so much easier without him realising that's what's going on until it's happening. He has the capacity to make things messy. Instead, I'm doing everything I need to make sure that at a date in the not too distant future, I will be able to withdraw from the relationship cleanly with minimum disruption to me or DC. There are two key events that need to fall into place first.
I have wrestled with myself, feeling like I'm being just as dishonest as he was during the affair. I might have come clean about my plan to leave earlier, but a few things has swayed me to keep working on my exit-plan quietly on my own: his own barefaced lying to both me and OW (whom, I'm sure, would never have let herself stoop if she'd known our relationship wasn't 'dead'), the idea of him pivoting from contrition to obstruction and manipulation the moment he finds out, making it much harder to leave, and his really unattractive assumption that, just because he's sorry, I'm bound to be up for forgiving him.
I think I will look back at this time as the weirdest in my life. I'm seeing some of the loveliest sides of him as he's trying to make good and I'd be lying if I said I'd not been tempted to keep motoring on with reconciliation. I really tried to embrace the 'never the same again, but different' ethos of affair recovery. But I couldn't, it was too sad and too humiliating after everything we've been through. At the point of disclosure, I wasn't able to leave, without taking some massive lasting hits, which I wasn't prepared to put DC through, and I'm so glad I didn't go then. By the time I do go, it will have been over a year since DDay.
I'm not sure if you'll come back to this thread, OP, but if you do; the long game is a viable option. No need to decide anything yet. Look after yourself.