Aside from that demon shapeshifting in what ever gender she likes (I'll believe her, when she says she is actually a female, as it would fit the harem route.), she tried to murder them on their last encounter and killed a lot of people. Not wanting to bed her under those conditions seems rather understandable. (It might be a trick to kill him after all.)
->So respect for pulling that sword and threatening to kill her, if she doesn't stop that shit at once. Most MC wouldn't dare that. And that was awesome, because it was prudent.