I agree with Edeneve that it depends how he told her and why he searched. It sounds like he told her in a confrontational manner accusing her of being all over the place online. Why else would she know about the results and say some are sites she doesn't even know about? I think he may have wondered what she was doing online and she knows him well enough that she suspects he was indeed checking up on her in a jealous manner thinking she might be doing illicit things. So here's where the motive comes into play. Most people could care less about a Google search because, as Pete's Princess said, it's common, public domain stuff. However, If I knew or suspected I was searched by my longtime partner (who I think should already know me) because he wanted to find something to either confirm his suspicions or to just see if he should worry, then I would be ticked off. But even then, I would not be all that upset, more like annoyed and a little hurt, but not crying. So I really think there is more to this, including background to their relationship. Imagine a long struggle with false charges of infidelity for example and then see how you'd react to being checked out, likely again. Maybe he accused her of wrongdoing and she has finally had it? Regardless, her reaction is one of someone who has had many things happen that have made this a straw that broke the camel's back. Clearly there is more background to her reaction. This sounds like a symptom of a larger problem for her.

As for dealing with it. You can ask leading questions such as how did she find out. What did she think he meant by this? What about it upset her? You won't get drawn into it and she will be able to vent a little. You just have to be careful to listen and support without picking sides; that should keep you out of it as well as not telling her how to handle it.

Now how is it you just said so succinctly what I took so much space to say? lol!