She may feel that if she confronts him, he’ll feel that she’s invading his space. But, if she goes about it the sneaky, hacked-way, and gets away with it; she’ll get the information she wants without the awkwardness. I’m not saying this is a good thing; because it clearly isn’t and their relationship is obviously unstable, and has zero trust…you’re completely right they should not be togehter if it’s like this.