I think it means that the relationship is only based on what they feel in the moment, and disregard what they had in the past with others, even if it meant a lot.
So, it's kind of sad because the singer knows that it won't last forever, and they're only fooling themselves.
I think it means that the relationship is only based on what they feel in the moment, and disregard what they had in the past with others, even if it meant a lot. So, it's kind of sad because the singer knows that it won't last forever, and they're only fooling themselves.