There are plenty of other friends out there. She doesn't need him, and its insulting to you. Tell her to put herself in your position. If you were talking to your ex, and she called you and was asking you questions like "what should I wear tonight?" and your response was "Oh hey, remember that one dress you wore when we were together, wear that, it looks so sexy." Not only would your girlfriend be seriously p*ssed off, she'd call a girls night and assemble the troops to mess that bitch up. Therefor; if you're telling her you have a problem with something and she's shrugging it off you should deffinately bring it up again. If she didn't insist on talking to him, you probably wouldn't have a problem with them occasionally checking up. She's giving you insecurities by not respecting how you feel. Be upfront and honest, and if she still acts as though her EX is her best friend, then maybe you should go have a night with the guys and forget about the bullsh*t for a night.