That is difficult.

I have knowledge of things that my girl has told me that I avoid speaking about. I'd love to know more about these events in her life, but they're really bad for her; triggers. For some of these, I'm not entirely certain she knows she told me, or how much she told me. I keep the information, don't bring it up, and use what I can of it to her advantage.

It gets hard though. Sometimes I consider talking about these things with randoms on Omegle or something, as it's anonymous & temporary enough, but am unsure if that's good to satisfy the urge to talk about it, or bad since I've been trusted with this info, and I err on the side of caution.

So, that's what I'd recommend. Err on the side of caution. Don't bring it up. Don't tell anyone. Use the information to help them if the chance to do so comes up.