"Soarin, please. All I'm asking is for you to- to turn around and look at me and I'll know you still care."
He inhales, then exhales, but keeps his back to her.
"Tell me you still want this. Tell me you still want to be part of our lives, hell, her life. This can't just mean nothing to you."
"Just leave, Clear Sky," Soarin mumbles. "I don't want you here right now. Take Windy with you. She doesn't need to see this."
"Don't call her that as if you know her," Clear Sky spits back. "God, she… she loves you, Soarin. You're all she ever talks about. She looks up to you and wants to be like you and she thinks you're the most incredible person in the world. I used to think it, too."
"Yeah, well, that's a lot to live up to, Sky."
Tears slip down the sides of her face, and she has to swallow to force her pulse down her throat.
"It doesn't have to be like this," Sky whispers. "I'll… I can forget I ever saw them here, okay? We can pretend it never happened. Windy's never seen it, so… so it's alright."
Soarin sighs, making it a point to make it as loud as possible. "I don't want you anymore, Clear Sky."
Her eyes shut tight. "Why did you do this with me, then? Why did you agree to start a family with me? This isn't about you anymore, it's about her. It's about all of us, because we're supposed to be a family."
"If it's cash you need, I can take care of you," Soarin says to the wall. "But I'm not ready to settle down with you."
"She needs her father, Soarin. Not money. Nothing could replace the presence of a parent."
"I'll visit."
Clear Sky bites down, hard. "That's not good enough."
Sooooo in my headcanon, Wind Sprint's father is Soarin! He does live up to the hype, for the most part. He spent time with Windy before his breakup with Clear Sky, he played with her, he loved her, and for a good while, he was a pretty good dad. But his relationship with Clear Sky slowly started to affect his relationship with his daughter.
Soarin cheated on her. A lot. He had stallions and mares over as if Clear Sky didn't even exist to him. As if he hadn't committed to being her boyfriend- her one and only- years ago. Clear Sky caught him in the act several times, but she stayed with him because they had a daughter, and she didn't want to rip apart Wind Sprint's world.
Why does Soarin cheat on her if he loves her, and if he loves his daughter? Well, there's never a good reason. But for one, he's famous. He's probably the most famous Wonderbolt, actually, at least before Rainbow Dash joined the team. Ponies everywhere admire him, and travel thousands of miles just to watch him perform.
He isn't an inherently bad person, though. He made several choices he shouldn't have, including committing himself to Clear Sky. He always knew he loved the fans' affection more than he ever loved the idea of a relationship.
He'll deeply regret these choices just a few years after their separation, though. Windy will eventually learn the truth, as much as Clear Sky tried to hide it from her (Sky didn't want Windy to see Soarin as a bad guy, she just wanted them to have a relationship. So she hid a lot of details from Wind Sprint, as any mother reasonably would). Soarin did visit, and he did send cash. But it was never enough.
By the time Wind Sprint is an adult, she is adopted by a very eager, very loving Rainbow Dash. By this point in her life, she wants nothing to do with her biological father. Soarin tries, though, he reaches out and sends mail and attends her flying shows and he really tries, but he's far too late.
Rainbow Dash doesn't know about any of this until about a year into her relationship with Clear Sky. It's hard for Sky to talk about it, which is why Dash never pushed her about it.