Disclaimer: Harry Potter and the Wizarding world belongs completely to JK Rowling.
As the spring of 1999 dawned, Charlie woke up one morning, woken by the light shining in to his bedroom in the Burrow. It was not often that he stayed there, now, as once the war was over he had spent some of his time in Romania, some with Lyra, and he had rented a flat in London to be nearer to her, as well as to all brothers that lived or worked in London - Weasleys' Wizard Wheezes for the twins and Ron, the Ministry for Percy, and Gringotts for Bill.
Ron still lived at the Burrow, staying there with their parents and Ginny, although she was still studying at Hogwarts for most of the year. Hermione spent her time drifting between her parents house and the Burrow. Although Lyra did the same, he normally stayed in London with her, and so it was uncommon for him to be back at the Burrow.
Now that Bill and Fleur lived at Shell Cottage, the room that the boys had shared from childhood was just his, now, and so it was to the sound of birdsong that Charlie woke up - alone.
The man blearily rolled over in bed, and as he looked over to the window and to the garden beyond, he suddenly realised something, and sat up in bed quickly, all traces of sleep gone.
He didn't want to sleep alone any more.
He loved Lyra.
He was in love with Lyra.
He wanted to marry her.
Those thoughts quickly led on to what would happen once she was his wife, Merlin, his wife, and his ears flushed as he got dressed. It wasn't until after he had departed the Burrow and had apparated to his flat that he realised something else.
He knew Lyra was proud of being a Potter. It was, after all, one of the few things she had that had been her parents'. Although Charlie loved Lyra with all his heart, and desperately wanted to marry her now that the thought was in his head, did he really want her to be a Weasley?
As he worked on some paperwork he had brought back from Romania, his mind was wandering.
If he didn't want Lyra to be a Weasley, if it meant her giving up something that had always connected her to her parents, grandparents and more distant family.. Could he be a Potter?
As Charlie thought about it more and more, the idea settled itself comfortably. He quite liked the idea of being a Potter if it made Lyra happy. He also knew that there were five other Weasleys who would pass on their surname. It wasn't necessary for him to do so as well. Not if it meant Lyra could finally have family who bore the same name.
Charlie paused in his paperwork, and dropped his quill as his mind blissfully drifted through the clouds thinking of children. His and Lyra's children.
Charlie had made up his mind. He would propose.