Ziggy Stardust said:

I dated this girl for two years, and we just got out of our relationship after I discovered that she'd been cheating on me with her boss, who is in his thirties. It's a terrible feeling.

That's rough man. I've sorta kinda been there (similar situation, different details). It sucks. The best thing you can do, in my opinion, is to treat yourself really well for a while. Eat good food, hang out with friends, do fun things you enjoy. I recommend chinese food, as you can pig out on it without much consequences. (depending on how salty it is I guess). You'll make it!