Dear RPW, I am partly seeking advice but not for a specific situation (I am currently single and not yet looking actively), and partly interested in starting a discussion in this post.

I would greatly appreciate your opinions on how to differentiate between, as an example, the assertiveness and leadership of a man who is truly 'Captain material' vs. the controlling and dangerously manipulative nature of someone with DT traits (psychopathy, Machiavellianism, and narcissism). Where do you draw the line between having 'desirable' Alpha traits in a boyfriend/fiancé/husband and Alpha traits verging into DT territory? I am already certain of the 'desirable' Beta traits in a LTR / marriage partner and thus I am not going to focus on that aspect here.