Wow, so the princess was supposed to marry Seika, but due to messing too much with the future she lost her chance. Now that's sad, I hope there comes a chapter where she's able to see a future with him, and then strives to make it reality.
The way I see it, she would've been used as political chess piece to tie him to the country because the oblivious her would basically have 0 chance of inheriting the throne.
But the more she studied and increase her value, the higher the odd of her inheriting the throne and thus the more wary her political opponents would become
In those future Seika would still try to protect her while letting her remain ignorant.
And once she got past a certain point, she became a politician and something that Seika have trust issue with.
So their future together can't happen anymore.
So on one hand, she lost the chance to be by his side.
On the other hand, she CAN help him now.