Sounds like a player. Regardless of the history between you two, my best guess would be he's bored with others and now returning to previous options! Or maybe he's not bored yet but trying to keep the options open! And using the emojis as the bate. So i suggest to not bite the bate! You are not together and as it appears you don't want to either so ignore or decline him nicely with a real serious manner and try to send him away by expressing your dissatisfaction. (If you done that make sure to not allow him to take advantage of your dissatisfaction as well)