Gina,
I agree with E, her advice seems sound. Consider that when your ex approached you in the restaurant, he was invading a boundary, which put your mind into chaos. If you need time with the new guy, take it. Its fine to go slow… just try not to backpedal into giving up your boundaries and letting the ex back in like that. His action in approaching you like that does not come across as affectionate, it comes across as petty, jealous and manipulative. Perhaps think of the action as an “anticoagulant” like a mosquito uses to prevent our blood from clotting so they can drink more. The resulting downward spiral is like the itch from the bite.
With warmth,
Matt