seriously? facebook? again?... I'd have slapped my little brother of 16 silly if he'd broken up with his girlfriend on facebook instead of in person (then again, I'm not sure who dumped who there).
for the life of me I cannot understand that anybody in their right mind would think it appropriate not to do such a thing in person.

also the "then you're being childish" bit ... tells me all I want to know really.
methinks you're better off without.
hard to hear, I'm sure, and I can't say it will make things easier for you or help in any way. I'm sorry.
virtual hugs, chocolate bars and pints of lager to you