Martin was heartbroken not for the first time in his life, but that didn't mean it hurt less. It hurt even more.
Of course, he couldn't really blame Steve for not loving him. As a guy, he knew that physical attraction didn't necessarily go hand in hand with feelings. Martin was physically attractive to Paxton, but nothing more. Steve has never suggested otherwise. It was Martin himself who built his hopes. It was he himself who introduced himself to this world of illusion. Therefore, he was solely responsible for his suffering.
Someone might argue that it was Paxton's fault after all, because he was the one who dragged Martin to bed and consequently into this strange, overvalued world where everything was upside down. Except that what Martin said was true - if it were someone else, than Steve, he would defend himself more. He gave up so quickly because it was Steve. Pxton was tempted by physical pleasure, but so was he. How can he blame him then?