Sixth year - Mary's POV
September, 1976
Sirius had promised he'd make it up to her. A part of her wanted to believe it- those words (and hands) could be very persuasive. Although deep down she had a feeling nothing would change. She was still mad about him forgetting to meet her in Diagon Alley for her birthday, although after shouting at him on the train and getting her feelings out, she had felt considerably better.
Despite this, she knew she could no longer ignore what was right in front of her. As much as she believed that he enjoyed her company (and other things), she couldn't bite back the feeling that there was something missing. There was a lack of true feeling. As much as he'd make it clear that he enjoyed snogging her, touching her, and having sex with her, the desire he displayed was surface level. There was no deep need or longing, even sometimes, he'd close his eyes and she almost thought his mind was elsewhere, that he was thinking of someone else.
Sirius was hiding something. That much was clear.
For the next few weeks a cycle had formed- they'd argue frequently, then have make-up sex. The arguing was tiresome, but the sex was good, she supposed.
He'd always tell her he was sorry. And that he did care about her. But there was a gaping whole in their relationship. It was always that he cared about her, never that he loved her. She knew he didn't love her, and she tried not to let it bother her too much, although after a year together, she couldn't wrap her head round why he would possibly stay with her, when he clearly felt no love for her.
One September evening in the common room, something clicked, and the answer to her question presented itself in the form of the tall, gangly, scarred Remus Lupin.
They were all in the common room, Sirius lounging on the sofa by the fire, Mary had her legs up across him, Peter and Marlene were engaged in a game of chess, James and Lily were out on their prefect rounds, and Remus was tucked up in an armchair, his nose in a book, as usual.
They had been having a jovial conversation about James' relentless pining after Lily, and how the redheaded girl had become marginally more tolerate to his antics than she had been previously.
'Don't let James hear you say that' said Sirius, snickering. 'He'd get his hopes up all over again'
'Potter's hopes about Lily are already sky high' she chuckled heartily.
Everyone joined in laughing about the matter, Peter had just checkmated Marlene's king, Remus smiled knowingly behind his book.
Once the laughter had died down, Mary averted her attention to her boyfriend, only to notice that Sirius' eyes were elsewhere, he appeared to be staring intently at Remus, who had put his book down and was adjusting his tie. Sirius' gaze was unbroken as he watched Remus' long calloused fingers work at his shirt button, loosening it. An odd look presented itself in his eyes, a hungry look, flickering with the unmistakable traces of what could only be one thing. Desire. Sirius' eyes trailed up to Remus' face, studying his features longingly.
Mary noticed Remus, who had caught Sirius staring, he held his gaze for a moment, something was spoken in that shared eye contact, however brief. There was an undeniable connection, something almost... intimate. Remus then raised an eyebrow, causing Sirius to look away sharply, a pink tint growing in his cheeks.
Mary tensed, as she glanced between the two boys, realisation creeping up on her. Memories of other exchanges she had witnessed between the two boys, that look in Sirius' eye that was only ever present when he spoke about Remus, came flooding back to her. Things that had meant nothing to her when they had occurred, all pieced together now. It all made sense now.
She withdrew her legs from where they had been resting on Sirius, and was about to get up and retire to her dorm, when James and Lily came clambering through the portrait hole, talking animatedly. The flushed look Sirius had previously displayed was gone as he went to crack a joke to James.
As Mary lay in bed that night, gazing up at the panels of her four poster, she dwelled profusely on the realisation she had made. The image of Sirius staring at Remus seared in her mind. The gaping hole in their relationship, Sirius' lack of desire when it came to her, everything boiled down to one thing. Or one person. Remus Lupin. Perhaps he didn't even know it himself, perhaps he was in denial, using her to mask it, or distract himself. But one thing was undeniable. Sirius Black was in love with Remus Lupin.