Remus liked his privacy, but he dreaded being alone.
He enjoyed the peaceful life he'd made for himself after the war – here, with Sirius. Grimmauld Place wasn't so bad once he and McGonagall got Mrs. Black's portrait off the wall and binned the mounted heads of the family's house elves.
At the very least, it was quieter.
Harry had given him the house and then moved out on his own, leaving Remus with Hermione's infrequent company. They had become friends over the years – slowly, as Hermione struggled to overcome her natural deference towards professors – and so when she'd appeared on his doorstep, flush-faced and bright-eyed announcing her graduation and subsequent acceptance in the Ministry, he'd offered her a place to stay.
It never crossed his mind that his privacy would be jeopardized by her presence, for Hermione had a way of filling up a room without making you aware of it. She was bright and charming – funny too, when she felt comfortable – and also sharp-tongued and headstrong. He quickly got used to the warmth and vitality she brought to the large house.
Six months later she was in Bolivia.
Grimmauld Place was anything but small, and with Hermione using her room about as often as Harry visited, Remus might as well have been its only tenant. So, when Sirius reappeared four and half years after falling into the veil, there was more than enough room for the new arrival. They'd picked up exactly where they left off and though the years had changed them it didn't matter much; they would always belong to each other.
It was easy to fall back into their old patterns and routines, easy to remember favorite foods and sensitive spots. They finally had the time to love one another and they fully intended to use it, despite regrets that they were twenty years older than they should have been. His Padfoot was back and Remus couldn't be happier.
Then Hermione returned from three months abroad in America. She'd heard of Sirius' return and had come back as soon as she could to welcome him; talk turned to bickering, which became yelling and at some point in the argument Sirius' made a caustic remark towards her honor and she'd disapparated. She suffered his company only one day more before running off to Sweden, her excuse: to give Remus more time alone with his newly returned partner.
Seeing her again – even for less than forty-eight hours – tore a hole in the world he'd fallen into upon Sirius' return from the dead. The world in which he had lived with Hermione – coming, going, books, warmth – now ran smack into the one in which he lived with Sirius – constant, hard, sex, heat – and he didn't know how to make them mesh together.
Since that first night, Sirius had entered into a tumultuous friendship with the younger woman, bridged by her infrequent visits; some times they were snapping at one another for days, and others Remus would find them sitting together on the tree swing, laughing at words he could never make out.
Each time she came back, he was jolted awake, as if from sleep; something about her pulling him from his comfortable world. And he didn't know why.
Sirius was too observant, too well-versed in the world's day-to-day routines not to get suspicious of what he was sure seemed to be odd-behavior on his part. He'd have to be careful not to show how flustered her sudden arrivals made him, or let his over-anxious mind analyze the phenomenon too closely. He couldn't let his own irrationality overstep the delicate boundaries the three of them had established; one inadvertent action and the house of cards would fall.