Mine doesn't really care, since I'm rarely on it when I'm with her. Because we have a long-dstance relationship, it's never a problem, especially since when we're together (like this week) I'm only ever on DTF when I'm waiting for her to do something so we can hang out or when we're just sitting around watching TV together and one of us has a laptop out.
Before our relationship became long distance, she did joke about it from time to time. But, again, I wa alway happier to do things with her than surf DTF.