There's an entire book series about it
"I'm home!" shouted Marigold as she closed the door behind her.
There were no answers at first, only the distant voices of a heavily-accented stallion talking to the phone, muffled by the walls. ". . . And what will she think about that? . . . Well, no, but . . . oh, so now you agree? Look, Daring, I—"
"I'm home, Dad!" the yellow pegasus filly shouted louder.
The voices stopped, and the door at the other end of the living room, the door to her father's study, opened. A gray earth pony came out with a smile and opened his hooves, offering her a hug. "Marigold, you're home! How's your day been?"
Marigold walked toward him and gave him a half-hearted hug, flinching as his emerald pendant nearly hit her eye. "Fine, I guess."
"What's the matter, sweetheart?" he asked as he took her saddlebags off. "Is it the physics test? I thought you studied hard yesterday?"
Marigold walked away toward the stairs. "Everything's fine, Dad. The test was easy."
"Sweetheart."
Marigold stopped in her tracks and gritted her teeth. "What!?"
Groom closed the distance between them and put a comforting hoof on her shoulder. "You can always talk to me, you know?"
She swatted his hoof away and turned around. "I know, Dad. Now leave me alone, I have homework."
". . . you can always talk to your mother if you—"
"No, I can't," she said curtly. "Even if I want to, she's always too busy for me."
Groom sighed. "Please understand her, sweetheart—"
"Understand!?" She trotted forward and poked his chest, right below the pendant. "Not even you can understand her! How can I, a fifteen-year-old, know my mother better than her ex-husband who has known her for decades!?"
Groom took a deep breath. "Look, Mary. We're still trying to figure this out, alright?"
She snorted. "It's been a year already. Will you still be 'trying to figure this out' when I graduated? When I got married? Or are you doomed to stay separated even after I also got divorced!?"
Groom reached out a hoof. "Mary—"
She took a step back and flared her wings. "Don't you 'Mary' me! Alright, you want to figure this out? Let me help you! What are you trying to figure out, exactly?"
Groom sighed in exasperation. "I told you, Mary, it's a lot more complicated than that!"
"Then answer me!"
Groom opened his mouth, then closed it back. He stood up and gestured toward the sofa. "Alright, Marigold. If it makes you feel any better, I'll try to think this with you."
And so the two sat on the sofa side-by-side, Groom staring at the floor in contemplation while Mary lazily drooped on the sofa's arm.
After a few minutes, Groom perked up. "I think the problem started when she decided to return to her career as an archeologist."
Marigold sat straight and nodded. "Alright, so she decided she doesn't like us anymore and her true passion is in digging dirt."
Groom chuckled.
Marigold looked at him in confusion. "You're not gonna tell me how it's mean, or something?"
Groom sat back and stared at the ceiling. "Well, you're old enough to know that."
She gave him an unamused look. "So now you're going to treat me like an adult."
He laughed and ruffled her mane, while she squirmed and protested, and said, "Not just yet, little flower. But your words do bring up old memories."
"Oh, alright. So your past is filled with banter and snarks." She nodded. "That's the next point, I guess. You liked her because she also liked you when you're still friends, and you two ended up getting married."
He raised an eyebrow. "Mary, what have you been reading?"
"Romance novels, obviously." She shrugged. "I'm fifteen. All my other friends are exploding with hormones. Why wouldn't I be?"
Groom gave her a playful nudge. "Well, there's no problem in reading romance. Just make sure you don't read those overrated vampire romance." He shook his head. "But to your statement, no. We never gave each other banter so much as cuts and bruises."
Mary groaned. "Please don't tell me you two ended up dating each other after a fight."
Groom guffawed. "We didn't live in a thrashy Daring Do fanfiction, sweetheart. But close." He looked at her and smiled. "Would you like to know how I met your mother?"
Marigold thought for a while and nodded. "Revisiting old memories so you can either remember why you love her or find out that you never loved her in the first place. Sounds good enough for me."
Groom frowned. "You're making it worse, you know that?"
"Just begin. How did you meet mom?"
"I was still an archeologist back then—"
"Just like Mother?"
"No, not exactly. Your mother was a thief."
Marigold stared. "Is this going to be cheesy with all that 'she stole my heart' thing?"
He grunted. "Are you going to listen or not?"
Marigold sat back.
"As I said, your mother was a thief. I unearthed artifacts to study them and complete the collection for my museum, and your mother stole them at the digging site, claiming that she's 'protecting' them from evil hooves, while in reality, she merely kept it at her secluded cottage."
"She sounds like Daring Do but evil."
Groom winked. "She kept doing that until, eventually, I nearly got bankrupted. I was desperate for money, and so I resorted to selling the artifacts instead. It only gave her more reason to steal from me. Years soon passed and I turned into a thief myself. Well, not exactly, it's more in the lines of tomb raiding than actual thiefery."
"I think I've heard this somewhere before . . ."
"That's because you probably have. It's the abridged version of how Daring Do and Dr. Caballeron met."
Mary threw her hoof upward. "What!? Is this some kind of joke?"
"Now, stay with me here." He smiled at her. "Your mother, A.K. Yearling, met me right after I published my first book."
"The book about exposing Daring Do's bad side to the public?"
"Yes. Considering she had done the same to Dr. Caballeron, it's only fair, don't you think?"
She huffed. "No. I think it's spiteful and unnecessary. I bet it had more drama than Daring Do's fanfictions combined."
"You clearly haven't read any of those fanfictions." He shivered. "Anyway, if I didn't do it, I wouldn't have met your mother."
"So, how did you two meet? Like, did she confronts you because you nearly destroyed her career, or did you two meet at a convention, or something?"
"Martingale and Yearling met at Tonatiuh, where Daring and Dr. Caballeron learned that Ahuitotzl was a Guardian all along, not just a monster."
"That's your first collaboration."
"It is. And that's when I learned that Daring Do is A.K. Yearling."
Marigold leved a stare. "Seriously, Dad? You think I'm going to believe that?"
Groom smiled and took his necklace off. Holding it with both hooves, he made a gesture that prompted a click from the emerald pendant, then gave it to Mary. "Hold this."
Mary looked at it in confusion. "Alright, why?"
"Have you been reading vampire romance?"
"Yes. Why did you—I-I mean, Yes! Wait! I mean—" She dropped the necklace down, and the green glow in her eyes dimmed. "W-what did you do?"
Groom took the necklace. As he wore it back, his eyes glowed soft green. "It's a much weaker replica of the Truth Talisman of Tonatiuh, a wedding gift from Ahuitotzl." he grabbed the pendant and stared at it fondly. "He told me it was to help us stay together and live as an honest family."
"Obviously it failed."
"Well, it failed to keep our wedding together, yes." He looked up to her and smiled. "But at least we're honest about it. And believe me now when I say this, as we should've told you long ago, that I, Groom Q.Q. Martingale is actually Dr. Caballeron."
Mary gaped. "B-but how!? I mean—wait, no, don't tell me that—"
"Your mother is Daring Do." He nodded, eyes still glowing. "So, that's the abridged version of how we met. If you want to know the details, you can read the book series."
"But that still doesn't answer the question." She shook her head and stared at him. "Why makes you love her in the first place? And, do you still want to keep it together?"
He frowned and put a hoof on her shoulder. "We're going to get back together eventually, sweetheart. I promise—"
She swatted his hoof away. "No, don't promise." She looked at him with pleading eyes. "I don't care if you forever get divorced. Marry somepony else, even. I just want you to be happy."
He sighed. "That's bold of you, sweetheart, but . . ." He stopped and stared at the ceiling. After a while, a smile formed on his lips and he looked back to his daughter. "I think we'll get back soon. You mother taught me many lessons in life, some of them helped me overcome my bad side and settled back as a history professor. It's your mother's turn now. She's just confused and wanted to get back to her old life, where everything was her, as the good guy, fighting bad guys."
"So, she's in denial that the world isn't as black-and-white as she thinks it is? That's . . ."
"Immature? Yes. But can you blame her? She had lived all her life thinking that Daring Do was the blatant good guy." He stood up and offered a hoof. "I think I'm going to visit her this weekend. Want to come?"
"That'll be great!"