No. Trust can be ruined in some point in your life, but it can be somehow rebuild and establish a different kind of trust. If you really want it, you have to give your best effort on trusting again someone. In my experience, I have a ex-gf who somewhat cheated on me. We'll its not that they meet or something but it's like it will go to that point that they will meet. [spoiler]I already told my ex-gf to stop thinking about her ex-bf. Her ex-bf already moved on and living in with her new gf. But eventually my ex-gf, and her ex-bf had a communication. She lied to me that they already stop talking and never will have communications with each other. One day, I went to my ex-gf house because we were going somewhere. While she was preparing on our travel, I called her girl best friend. Then eventually her best friend confessed to me that my ex-gf and my ex-gf's ex-bf were talking to each other and they might meet again. I was furious that time knowing my ex-gf lied to me. [b]But I decided to stay calm and hold my emotion inside[/b]. I talked to my ex-gf and confronted her about that lies. I asked her if she loves me and if she still have feelings for her ex-bf. And she said yes she loves me but she can't love me the way he loved her ex-bf. And also she said yes, she still had feelings for her ex-bf. I become numb that time. I didn't know what would be my reaction. But I remain calm. While she was sitting on the bed, I got on to my knee and ask her calmly, "Do you want our relationship to work out? If yes, let me help you on that issue. I'll do anything for you and to let you forget your ex-bf" And so she said yes, eventually we became open to each other. Our relationship became more stronger after that discussion.[/spoiler] Serious talking and understanding your partner are the best solution of these kinds of events. Before you made a drastic action, you might need to rethink and became mature enough to accept that all people will not fit into your expectation.