Preselection, women being attracted to men already in relationships, is widely documented. It has evolutionary roots as an individual already in a relationship has been vetted, therefore being "preselected." The downfall of it, however, is rather obvious. A person willing to cheat or end their previous relationship to be with someone else isn't trustworthy or reliable. Loyalty is a trait people are inherently attracted to, so as not to be cucked and lose resources or lose access to them. A single mother in nature cannot survive alone, and if the baby daddy is cheating, then there's a fear that his resources may not be allocated to your offspring. Preselection is therefore an example of human hypocrisy, and evolution being what evolution is. An imperfect process.
