It could be referring to how he is higher than him now even though he's the new boyfriend. It could also be about how shes placing the new boyfriend above all her family and all her friends. That's why he says Our love, let it pass, because he'll eventually get over her but he has to get this off his chest. "What is this coming to i am unwilling to go" - he's still not over her and the final lines refer to how she has lost someone so great and that he has lost, so in reality, at the end of a relationship -- no one wins.">
I have to agree with Ixes. This is most likely about a relationship that has ended. The specific reference to "You used to be like my twin and all thats been was it all for nothing?" That's a reference to the two individuals past after they ahve broken up, most likely after a long relationship - or perhaps a divorce. When he says, are you stronger when you are with HIM -- him can just refer to the new boyfriend. And when they say "Placed him above us all" --> It could be referring to how he is higher than him now even though he's the new boyfriend. It could also be about how shes placing the new boyfriend above all her family and all her friends.
That's why he says Our love, let it pass, because he'll eventually get over her but he has to get this off his chest.
"What is this coming to i am unwilling to go" - he's still not over her and the final lines refer to how she has lost someone so great and that he has lost, so in reality, at the end of a relationship -- no one wins.