Oh my god you poor thing, Jesus Christ.
Can your sister come stay with you for a few days at least?
Bloody hell, men who do this are simultaneously pathetic and so fucking cruel.
Be prepared for the script:
"I booked prostitutes but never went through with it I just liked the thrill" etc. Then he'll blame you for 'breaking up the family' and threaten to kill himself. Then he'll get nasty and surprise you with just how selfish he is about the divorce and kids.
BUT that is all (relatively) short term pain for long term gain. Being free of a relationship someone like him and the anxiety they cause is fucking priceless.
Because until the end of time, he will lie and lie and lie to your face until he is caught unequivocally red handed on an individual fact. And then he'll admit to the minimum version of that fact and continue to deny everything else.
You'd spend the rest of your life anxious and waiting for him to fuck up again. And every time he did it again, your self confidence would take a further hit meaning the next time you're less likely to leave as you doubt yourself.
Compulsive cheats and liars like him aren't wired like us. You cannot reason with someone unreasonable, so don't get in to big back and forths where he can wreck your head even more. He's toxic and he's done a number of unforgivable things.
Lean on your sister and friends, let people help you.
We are here too.
I'm so sorry 