At least that part of it is done now. It's out in the open. You can breathe easily, you can rest, you can go at your own pace.
Imagine if you had waited the six weeks, this would have broken you. Does he give a flying fuck about that? He would have carried on lying to you whilst you tied yourself in knots trying to hold everything together.
Now you are considering putting yourself in a similar position. Trying to live with him, act normal around the children, talk about day to day matters, all the while seething and going mad with wondering what he's not telling you.
Just tell him to leave. Honestly, it doesn't mean it's over, it just means that you have some space to think about what you want to do next.
You don't have to rush into counselling. In fact, you should probably wait to let this all sink in and prepare for the next round of revelations which are sure to come yet.
You are putting your needs at the bottom of the pile again.
You need to have your house to yourself, to speak freely with family and friends, in your own home. To have a place where you can scream and sob and let it all out. To have space, to think, to give your poor tired brain a rest, to recuperate your shattered nerves.
You must feel like you're run a marathon or something. Take some time to rest. Tell him to leave. It's ok to do that, it doesn't mean forever, it is what you need and deserve right now. If he has one jot of compassion for you, he will understand that.
And if he goes to her, then you have your answer.