In Vain

'cause if you sacrificed everything, it'd better not be in vain'

ok so can we talk about this song! Wait first of all i have to give major props to Jazmine Sullivan her songs are always dead honest. She wants to break the windows out his car. Yes we all thought about it! She's in love with another man yep open, honest and straight to the point. She's not scared of lions, tigers and bears but she's afraid of love! Who isnt afraid of love! What a brilliant writer, please please dont leave music!!!
Ok back to the song! So from listening without paying attention one would assume she's wishing the best to the guy that left her. Hopes his new woman treats him well, in fact better, that he's happy etc. It's only when she says 'cause if you sacrificed everything, it'd better not be in vain' that i realised how subtly sarcastic this song is. She really isn't wishing you the best. She really doesnt mean 'i hope she's everything you want and everything I wasn't'  In fact she only hopes for your sake that it was worth it, that throwing away everything you built was worth it. Why? Well because it would have been in vain. Vain: not yielding the desired outcome. And the assumed desired effect would have been that the grass was greener on the other side, not so? Think of it as building a house from scratch and then falling for some wheeler dealer who has some cheap prefab houses. For your sake one would hope that this prefab doesnt fall apart because your other house has already been sold! 
Yes Jazmine you speak the unspoken words of many victims of love gone sour - 'cause if you sacrificed everything, it'd better not be in vain'