(though no doubt this can be explained by his thinking that his own fears are irrational in the first place, and thus assuming that level-headed Harriet couldn't possibly feel the same).

I think he's too caught up in giving her things to make up for past wrongs (his own and Boyes') and includes the house in that, forgetting that it was her contribution. So he feels responsible for designing everything and for it going wrong. And his version of thinking of her is to just give in to whatever she wants/decides, when really she'd much rather have an adult-to-adult discussion/argument and a mutual decision. I mean, to find out whether *he'd* want to stay after the corpse turns up, she has to ask Bunter.

I'd like to know more about Harriet/Boyes to find out how she emerged far more competent at relationships than Peter. I suppose with only business-arrangement mistresses and Bunter (as a live-in servant who does what he's told, stoppit) to go on, he has some excuse for not having a clue.