I'm assuming she's been "kidnapped" and it's become so by the book and expected, she doesn't care and just treats it like a second home.

Which, I mean, guy should be fine with that. Gets the Princess living with him, calling him Darling, showing off what she's been hiding underneath that dress.

Let's be honest here, Peach basically lives about 1/4 of her days with Bowser in his castle. The fact that they play sports and go karting with each other means that the animosity doesn't extend beyond it. They are basically weirdly antagonistic pals at this point.