Umm......help!!!!?

ok so theres this guy that ive dated before about twice n we split up a couple of months ago,weve resently been texting eachother quite alot and he said that theres alwayz a chance that us two could get bk together! I have loved him since the word go, and when we split up i found it reli hard! but ive been going out with this other boi and hes reli sweet but i just keep thinking about my ex. What can i do?