Jones - sending you lots of courage for today.
Is there anyone in RL who you can open up to? Perhaps they could come round for the day or weekend? I agree with others that he should leave and give you space.
Don't concern yourself with where he would have to go, that is his problem and he is capable of driving an hour or two.
Could you ring his parents and explain what has happened, asking them if he could stay there for a few days while you digest. Makes it hard for him to play the 'I've no where to go' card and also makes your in-laws aware of what's gone on before he starts to paint you as the bitch and himself as the wronged party.
I've been through a far milder version of this and that was so upsetting, so I can't imagine how you're coping with discovering an actual affair. It's 6 months down the line for me and the trust isn't back yet, I still check his phone, I still think of it and I get very upset at times. Make of that what you will.
I'm so sorry, no one deserves this. It's a horrible thing to have to deal with. Agree with a PP who suggested going to your GP and getting signed off for a week or two. You won't be any good at work with all this running through your head.
Try and get some rest today and really think about calling a friend or relative over for a couple of days to help you.