In her perfect reality, Santana would have ended up with a girlfriend after spilling her guts to Brittany, instead of a broken heart. She would have won prom queen, and danced with her favorite girl in the entire world, in front of everyone, without shame. She would sing and dance on stage with her. She would kiss her whenever she wanted to, just because she could. She would just be with her, always, because that would just be enough. She wouldn't have to worry about anyone judging her because she'd be happy, and that would be the only thing that mattered. They could buy an apartment and live together in the city, and maybe someday, they could get married, because they both would want it more than anything else in the world. And then Brittany would be hers, officially. And they'd be in love with each other and everything would be perfect and they'd be together forever.
But Santana doesn't live in her perfect reality. She lives in a world where the girl she's in love with won't break up with her boyfriend for her. Where she has to deny the way she feels because she doesn't want to be made fun of. Where she dates someone she isn't in love with, at all, just as a cover up. Where her date wins prom king, and a boy wins prom queen instead of her. Where she's too scared to sing and dance on stage with the girl she's in love with. Where she can't even admit to her best friends - scratch that, her family - that she actually likes girls, and always has.
For once, Santana wishes that her expectations would match her perfect reality. In her dreams, she lives in that world, where Brittany is hers. But every time she wakes up, her heart breaks a little more, knowing that she doesn't live that life. But she puts on a strong face, and goes to school every day anyways, and just admires her from afar. And she tries not to break down, because seeing her dream girl being happy with someone else is the most painful thing she's ever encountered.