He knew that Gwen was keeping something from him. He suspected it had to do with her job. Sure, he believed that there were things she couldn't tell him, but there seemed to be more to it than whatever she was doing in Special Ops. Special Ops didn't have you leaving at three in the morning after a call. There couldn't be something going on in Cardiff that was that important.
Those nights she left, he worried. As soon as she was gone, he was sitting up in their bed, trying not to think about her getting harmed.
When he saw her this morning at the crash site, the curiosity piqued. Especially when she flat out lied about knowing about the accident. How could she just lie to him like that? When she left, he followed him, wanting answers.
Rhys never thought that Gwen was doing something like this. Catching aliens! He couldn't believe it, but even that pretty boy, Jack, and the others, and that alien those bastards were carving up. As unbelievable as it seemed, it did seem that Gwen had finally let him in.