Headcanon: Professor McGonagall has a muggle wife she never mentions to the students, because they never ask.
Four years after Harry’s left Hogwarts he visits McGonagall’s home to talk her out of retirement, and the door is opened by a woman he doesn’t recognise. Confused, he introduces himself and asks to see McGonagall. The woman recognises the name and invites him in, saying Minerva will be home soon. She then talks a mile a minute, but not about the war - about the stories she’s heard about the golden trio from their head of house. About how Harry stood up to Umbridge, and how clever Hermione was, and how Ron had been able to beat her chess game, and how PROUD Minerva was of them all.
By the time McGonagall does arrive, Harry and her wife are chatting like old friends. Minvera’s wife calls her things like “Darling” and “Pumpkin.” Harry cannot believe his ears.
Harry is invited to tea every Wednesday from then on. He always looks forward to it.