Okay, so, have I been missing something incredibly obvious this whole time? In Guards, Guards!

And then it arose and struck Vimes that, in her own special category, she was quite beautiful; this was the category of all the women, in his entire life, who had ever thought he was worth smiling at. She couldn't do worse, but then, he couldn't do better. So maybe it balanced out. She wasn't getting any younger but then, who was? And she had style and money and common-sense and self-assurance and all the things that he didn't, and she had opened her heart, and if you let her she could engulf you; the woman was a city. And eventually, under siege, you did what Ankh-Morpork had always done--unbar the gates, the let the conquerors in,  and make them your own.