Search Results: problems with fiance

4 weeks ago everyting seemed fine and happy.

3 weeks ago I noticed a video chat app installed on our shared phone and a single guy on there with a list of multiple (at least 15) past call type things. And his phone number. I curiously typed in the number and his number was listed as her cousin (the ousin is a girl)
She told me he was just a friend, but wouldn't explain why she hid his number like that.

5 days ago, I noticed a flight booked at a cost of $1000 and she told me she was going to take the boys to see her mom in the nursing home she is in, and check out a few places where we had planned to move.

4 days ago she was napping and a text came to our (shared and only) cell phone from the previously mentioned guy. Overcome by curiosity, I text back.
Him: "Hey my love"
Me: "Hey"
Him: "One more day"
Me: "I can't wait. Whats the first thing you wanna do?"
Him: "U"

I woke her up to inquire and she went ballistic. I took our kiddos out of the house since she was going to be getting him from the airport that night. His flight got pushed back and she calls me like nothing is wrong.
2 days ago: SHe picks him up and I had told her that I did not want them in our apartment. I stopped by to check and grab a toy for my kiddo and heard them inside. I called and pretended that I was going to be grabbing something and she said they were at a hotel and she was home. I told her I was pulling in and she quickly asked me to wait because they were there.

She spent the next two days with them, not talking to anyone, acting extremely flaky and then ended up driving them 650 miles to their hometown.

$1800, 4 days, and 3 nights, 2 guys later...
She's on her way home now. I'm devastated and hurt by the lies, was unaware of any issues between us, and now have to deal with near divorce like problems. How would you handle it? Try and make it work if she wanted to, or throw away 6 years that tested your resolve at times but were overall very good. Could I ever trust her again?