"I love you, sweetie," Remus's mother says, but Remus feels- knows- that she doesn't. He is standing at the precipice of the crowd that is formed around the Hogwarts Express. The cool air is making his eyes water. His mother turns to go. His father didn't come, he didn't bother. Remus knows that his father is appalled by him, he sees the thinly veiled disgust on his face when Remus retreats to the cellar every month.
Remus knows that his parents don't want him. They are always away from the house, hotel-hopping, leaving him alone without warning. Remus doesn't miss them when they are gone, and he is sure that they don't miss him.
Steam bursts from the train, so Remus climbs on board. Already his mother is long gone. Remus wonders if she is relieved to be rid of him. He assumes she is, but probably feeling at least a twinge of guilt over it. But not enough guilt to hide the pills she has stocked in the bathroom, untouched, just in case. Sometimes Remus would take out these pills when his parents were away. Sometimes he would even pop off the cap and roll them around in his hand. It was a strange feeling he gets from doing this, and it tastes like power and weakness and strength and acid.
Remus doesn't care what feeling he gets from it, as long as he gets one. That's why he still hangs around with James and Sirius, even though they mock him every moment they can, and accentuate it with a friendly punch.
Remus wonders if this qualifies him as a masochist. He doesn't want the pain particularly, but he'll take anything to fight off the numbing feeling that has enveloped his life.
Here are Sirius and James now, laughing and smiling. Remus opens the door to the compartment and steps inside. The two greet him and watch with amusement as he struggles to heave his trunk onto the shelf above.
Remus settles down and watches James and Sirius. He notices, if no one else does, the way James looks at Sirius almost lovingly, and how giddy he'll get from just one compliment, one touch. But Sirius doesn't swing that way, as he vehemently ranted about when he revealed that a fourth year was hitting on him.
James knew Sirius would never return his affection. That was why Remus won't be surprised when James sneaks into his bed later that night to kiss him. Remus knows he is being used, but sometimes, at least in Remus's book, that is okay.