Girlfriend still "creeps" on her ex?

[sport chevette]

We've been together for almost a year yet it seems she still may want something with her ex... She looks at his tumblr any day she gets on her mac so that's basically daily and im sure she looks at his facebook and twitter also... It wouldn't be that big of a deal but I mean its a daily thing, she knows I know because I bring it up occasionally and all she ever has to say is that she feels bad how things ended with him and she wishes they were friends like they said they were going to be. She also says I look into it the wrong way or to much... But I mean its almost been a year, to me that means your obviously not over it if you creep on someone that doesn't talk to you or anything... Im in a shitty mood about this any time I think of it so what should I do? has anyone ever creeped on someone like this and actually not wanted to be with them? any advice or experiences are welcome. Thanks