If we're considering the BJ scenes, there are only three with her, and just two in doggystyle. That's surprisingly low for someone who's arguably the best-looking character in the game, if you ask me.
Think part of that is due to the narrative progression. Early on in previous versions, she was very much 100% Grandpa only(she loved him, wanted nothing else). It's only been in the more recent updates that some of that has changed (I don't remember how much of her now vs old is different, it's been a good minute).
So with that in mind: if she's committed to another, why make content for her until that mindset changed.