Hello OP.
so sorry to read this. You have received some good advice here and I will echo what others have said - this is in no way, shape or form, your fault. Ok......? It is really important that you understand that.
He has been detaching from you, emotionally checking out for some time.
Sadly there is a script and it goes like this.
He will deny
He will delete (think he may have started doing this)
He will minimise. By minimising I mean he will try and say they only met once, only kissed once, and then my favourite he couldn't get an erection to have sex.
You know this isn't true. You have seen the email evidence.
You need to try and stay calm as I think you are going to confront him when he comes in at 3.
You need to ask him about it, if necessary bluff a bit.
Something like, 'i know that you have had at least three affairs since the DC have been born. I need you to tell me about them now'. (I know you said two, but if you say three, he may say, no it's only two!!)
Then you must be quiet. There will be silence but you must not fill it. If he tries to deviate, bring him back to your point.
Personally I said in answer to his cheery hello, are you alright,
' no I'm not and I want you to tell me all about xxx xxx' his face was a bloody picture!
He may cry and say it means nothing, a mistake, he loves you blah blah blah.
You need him to ring the OW on speaker phone and finish with her.
You then need him to leave for a few days as he needs to see, first hand, what separation from you all is like. You need to use this time to decide what you want out if all of this. Can you try again, because you can if that's what You want. For this to work you need total transparency and honesty from him. This is not the easy option, trust me!
Sorry if I've gone on a bit
but this afternoon is important. And I wanted to try and help you to get it right.
It's horrible. I know it's horrible.
Always here to hold your hand 