I know photos are in LOK and I don't think they were invented in ATLA but let's all just overlook that little detail k thx :)
In My Heart
Izumi pointed at the page, "That's a cute photo of you and Uncle Aang, Mom."
Katara hummed, looking at the old gray photo of her and Aang with their arms around each other. "Yes… that's back when we were dating."
"What? You and Uncle Aang dated?!" Haruki shivered in horror.
Izumi's jaw was dropped and Kya screeched, "What about Dad?! And Aunt Toph?!"
Katara chuckled, "Yes, Uncle Aang and I dated when we were younger, before he got with Aunt Toph. Your father was dating Mai at the time." She found a picture of them together shortly after Zuko's coronation.
"Auntie Mai dated Dad?!"
Izumi furrowed her brows, "But isn't she- you know…"
Katara laughed again. "It's okay to like both boys and girls, you know? Auntie Mai and Auntie Ty Lee are married now, but they both dated boys in the past."
"Oh…" Her kids all chimed in new understanding.
Haruki shook his head. "You all just… dated each other? And stayed friends?"
"Of course we stayed friends! Strong friendships can transcend lifetimes, and awkward breakups. True friends will always be in your heart."
She turned the page to show a huge group picture of all the friends together. Kya looked up at her with her big blue eyes, "Will you tell us more stories about you all winning the war?"
Katara closed the book and smiled as her youngest daughter climbed into her lap. "Alright, one story, and then it's bedtime."