There must be a reason you two broke up. Does he want to get back with you? If not, it is very selfish of you to use something to get him back. Eventually you will just break up again if you do not fix what broke you two up in the first place.
Try talking to him?
And people on here do not like to cast spells for others.
And judging by your profile it seems like you know nothing of magick at all. Which then, if true, you should really study the basics such as meditation, grounding and centering, before you try to cast a spell. You cannot just chant something and hope it works.