I think a lot of us have been in a situation where we find ourselves as the friend with benefits. Of course this is a mutual thing, it's not like one person isn't really into it. But the thing with the Friends with Benefits situation is that it never lasts. Not in my experience anyway. Someone usually catches feelings while the other does not and Prawn's Thalassa kind of gets this.
It gets it from the perspective of the person who has feelings, that is. There isn't anything more disheartening than knowing you feel strongly about a person while you know that they don't feel the same. It feels like a weight on your chest, a stone in your stomach; one that's causing you to constantly sink.
Notable Lyrics (again, basically the whole song):
We gave our bodies. You made something feel whole again inside my feeble body. I want to be good, I want this right. Let’s flood this over. I’m glad you found clarity in ambiguity. I’ve been awake, while you’ve been away.