So he called you "just to say 'how are you?'" but somehow the conversation evolved into a comparison between you and his current girlfriend. No, she doesn't do the things you used to, she doesn't dress like you, they've had an argument and he is isn't happy. As the conversation goes on he reminds you of the things he loved about you, the way your hair smelled, that outfit he thought you looked smokin' in, 'remember when we went to________?' (insert all types of nostalgia) Finally he says, "hey when can I see you? Let's hang for a bit."
Now you're caught jonesing- STOP IT!
Girl, snap out of it! Do you really want to be his "safe option" the one he can return to just because his current girlfriend upset him. You're not a monster and that's why you answered the phone or that text message, you care and maybe you're one of those people who can remain friends with an ex without wanting them back- EVER. However, this is where you need to draw the line.
*No meeting up- There is a reason behind that meet up. It would feel just like the good ol' days and you do not need that, especially from some one who is not available.
*If you must talk- Keep alert and make sure the conversation does not stray to 'NO GO' territory (this includes propositions of all sorts).
*Make a commitment to yourself- You will not be some one's consolation prize, second place or safety zone. You deserve to be the only option and priority.