I took her along only when needed and got her cured as soon as the quest line was done. In the same way that joining the Companions partially ensnares into evil, it ends with redemption from it and so as long as the conclusion pleases the gods, it's fine. If a given knight feels guilty about it, they can find an act of penance to perform, like climbing the 7000 steps again or doing a great act of heroism that aids the weak.
I took her along only when needed and got her cured as soon as the quest line was done. In the same way that joining the Companions partially ensnares into evil, it ends with redemption from it and so as long as the conclusion pleases the gods, it's fine. If a given knight feels guilty about it, they can find an act of penance to perform, like climbing the 7000 steps again or doing a great act of heroism that aids the weak.