I've always thought that the reason women choose other careers than STEM is that many STEM jobs tend to be done in isolation, and that many women (whether by nature or nurture; it doesn't matter which) tend to prefer work with more human interaction.

An anecdote that can be generalized across many couples I know, is that I enjoy going to my workshop and working on a project by myself for 4-6 hours at a stretch. It's relaxing to me, helps me focus my thoughts. My wife likes to do book clubs and meets with friends to discuss political and social issues for similar stretches of time. I find her hobbies to be a bit stressful and occasionally boring, and she feels the same about mine. I think this has really shaped the careers we've pursued.