Why do so many people associate love with breathing?

All of those songs: I want you so bad I can't breathe, how can I breathe without you, why can't I breathe whenever I think about you? Is loving someone really as vital as breathing? Will we die without that "other person?"
I've tried not to but he's all I've thought about this entire trip. Without even being aware of it I find myself looking for him, listening to sad music in tribute to our lack of communication, hoping he's in that car that passed me as I walked the dog on the sidewalk. Even if he was in that car though how would he recognize me? He'd have as much luck as I would have in recognizing him whizzing past in his car. These two weeks have just shown me that it's not meant to be. If we can't find each other in this small town how will we ever find each other? It doesn't matter how hard I try not to care about him; any amount of attention he gives me, any sliver of a chance that I might get to see him and my heart jumps up and down. Stupid heart. (love is for kids.)