I'm An Opportunistic Princess In-Charge of Solving Things

Princess Octavia was a high school girl until she was reincarnated into her beloved BL novel's world. The fact that she's able to see her brother, the main character, and his lover so closely is a good thing, but both of them are male. If so, won't there be trouble with future heirs?! There's no way they'll make her take a political marriage to offer them a child, right?! I don't want to be a character who's taken advantage of like that! If this is how it would be, I will surely find my own partner to be happy.....!!!