You're wasting your time, you're driving yourself crazy with this question and you're making yourself hurt more. There might've been signs but you just missed them. Accept that she won't tell you who he is for whatever reason atm, but that it doesn't matter: she did this on purpose, she's still doing what she's doing on purpose because she still wants a divorce. She could've made it all up but that doesn't matter: she still wants a divorce. She still wants to go to her parents.
Stop.
Take a deep breath.
Accept that you might not get the answers you need/want.
And then do what's good for you. Take/Send her to her parents today because sharing a space with her - unless you want to work it out somehow - is bad. You're asking/doing the same thing over and over and you're not getting a different result. She's so far in to her head about what she wants (and probably guilt) you won't get through to her or get the answers you want.
Then give her 2 weeks to initiate divorce proceedings and if she doesn't then you do it.