Caught my GF Having innapropriate conversation with another guy who is her "cousin"

My gf and I are very much in love. While she was on a trip, with her mother to meet extended family, she seemed to be a bit less chatty than usual. Upon her return, I had a bad gut feeling. Like an asshole, after asking her if anything was on her mind and receiving reassurance, I decided to search through her phone. Bad move on my part.

I discovered a conversation with her supposed "cousin" with innapropriate comments. She said he was cute. He said until I bite you. She said 😮 cheeKY. She sent him a pic of a new dress- which was meant for me- and he said looking hot as ever. He said goodnight beautiful, she said goodnight handsome😘😘.

No where was I mentioned. In any conversation. Supposedly she talked about me with her family while there.

I explained to her what I had done, told her how it made me feel. Her reply was somewhat vague, then was upset about me going throught her phone. He also mentioned something about leaving his gf. My gf also has been raving about how much she loves England and wants to go back there.

She doesn't like the city we live in and wants to move. Which we've talked about and I'm willing to do.

Now, to me, it's pretty ******* obvious that those types of conversations are wrong. She doesn't seem to think so.

By nature, I tried to ignore it over the past few days.. we've spent them together and have shared laughs and love and reminisced.. but she is still talking to the guy and every 20 to 30 minutes my mind floods with how fucked up that seems and how I wish I had never saw it.

I need to get opinions on how to approach this situation as we do really care about eachother an love eachother. I feel that what happened is she isn't fully satisfied with her life but because of her feelings for me is too scared to talk to me about it for fear of losing me. I just want a real answer from her. No bullshit.