Counterpoint to popular headcanon : In my opinion, Lars is very much not asexual. Don't get me wrong, I love asexual Lars hc, I'll read fics about him, I'll write fics about him, but in the movie, Lars is very much not asexual. It's part of his problem.
Lars is traumatized by sex. I don't nescessarily mean that he was abused in that way, the movie doesn't tell us that (it's left vague). What I mean is that probably the first thing that Lars ever learned about sex is that it makes babies. Babies that kill mothers, and destroy fathers, who then hurt the baby. I think he would love to want nothing to do with it. But then Margo shows up. So he goes to work and he desires her, and he's inundated with sex there thanks to his pervy coworker. And then he goes home, and the reminder of what sex does is aggressively asking him to dinner.
Sex = death, and he's so afraid Karin is going to die, and he's so afraid of Margo and how she makes him feel, that he has this life-ending potential in him, so he blows off energy spending time with his wood (heh, metaphor), but it's not enough, it's like a runaway train, and it's making him more and more stressed until he snaps. And then Bianca.
I know I don't have any more insider knowledge about the intent of the screenwriter than anyone else, I'm not speaking from authority. It's just, I watch that movie and sexual anxiety is all over it.














