awww....my ex did that to me too. we broke up a year and then he contacted me again. i don' t know what his intentions were for calling me back...and so i gave in to him and talked to him. things didn't worked out and he left me again this time. now that i look back, he only came back to me because he's lonely and needed someone to talk to..and i was the person that he trusted and who knew him more where he felt more comfortable with me. i was his comfort zone and that's why he came back.
my advice to you is, if you don't love her like before anymore, if you have no intentions of getting back together with her anymore, if you don't see yourself with her in the future, then don't give in to the temptation. don't respond to her emails. don't contact her. just ignore her completely. sure, this may be harsh and cruel, but you're only doing this for your and hers sakes. she's probably vulnerable right now and you were her comfort zone so that's why she's coming back to you, but don't give in. eventually, it will be better for you both.