It wasn't a surprise.
It wasn't a surprise that Jason chose her over you. You saw it coming from a mile away. You saw it coming the moment she greeted him when he stepped of the Argo II. As a daughter of Aphrodite it's kinda your job to spot and seal true love.
It just hurts when the guy you thought you were in love with is in love with someone else.
You started to drift away. Away from the world, away from the living. You slipped away into a shell. A strong, unpenetrable shell. At first, you were sad. Then you were angry. Then, when all those emotions wiped away, it was like you just forgot how to be normal.
But honestly, were you ever normal?
He broke that shell. Him, the one you never thought of as any more than an (annoying) friend. The little latino elf broke your shell, like he was breaking open a box that may or may not have treasure in it. Slowly, as to not break the goods, but breaking it open all the same.
Like you could be considered treasure.
And you gradually started to fall in love with him. You were scared. Of course you were, after what had happened before. But there was no denying it, you liked the fiery little hephastus boy.
But did he like you?
Then you caught him kissing a girl (one of your sisters, no less). No, caught wasn't the right word. He was allowed to kiss her. Why wouldn't he be. They weren't dating or anything. Heck, you hadn't even told him that you liked him. So you slipped back into your shell, making it harder, more durable. Leaving the little builder to wonder where his friend had went.
He never saw you as anymore than a friend.
Leaving him to his girl, and Jason to his. Your love life was cursed. No matter who you liked, they were going to hurt you.
Crush you, burn you.
And so even today you're still in that shell, still watching the world through a glaze. Face like a slate, showing no emotion. Heart withering away with every time you catch a glance of your sister and him kissing in the cabin, everytime she comes back late with her hair messed up and her eyes bright.
Everytime she was with him.