My fiancee had problem with her phone and used mine to

My fiancee had problem with her phone and used mine to sign into her FB and forgot to log out. When I put on my data days later, her messenger chats poured into my phone. And below are the excerpts of her chats with one guy man ‘like that’ she met online. This is the same girl who has refused me access in between her legs until I pay her bride price, to which I have already kick-started the process to that effect.
She came to my house yesterday to demand for money to buy Brazilian weavon to make her hair unknown to her that I’m now aware of her little secrets. I have asked her to leave for her parents’ house but she’s insisting to know why I’m being cold to her, as if she is oblivious of her escapades behind my back ?. So far, I have remained calm and haven’t spoken to her about my discovery because I’m still shocked? and at loss for words to begin with. What’s the point of asking her when I already know she would deny, but for the overwhelming evidence I have. I just want her to leave. You may wish to know that the date on the chats I screenshot tells the day and time she would meet with the guy man and corresponds with the date she told me she attended a friend’s wedding somewhere in Aba. The friend I don’t know.And her phone was conspicuously turned off ? althrough that day . She was unable to convince me beyond all reasonable doubts why her phone was switched off for she has fully charged powerbank. Because of the love and trust I had for her, I didn’t push it any further than I already did. I am heartbroken.
Somebody tell me how to go about this please