Or just let it go, stop giving him any of your energy and focus on moving yourself forward in a strong, positive way!
Sorry about the break up. Those are always rough. The good news is that there are heaps of men. They're everywhere. (Admittedly, a high percentage of them are idiots, but there's no shortage of them.)
"Losing weight is easy; I've done it dozens of times."
(with apologies to Mark Twain).
Ultimate goal: Size 10 clothing.