When we look at the origins of the "life partner" assumption, they are grounded in a time when people lived in a much more networked social environment than today's. In other words, people had many more outlets for social and emotional contact, as well as more hours working - and probably spent much less time 1:1 with their spouse. AND the overall social and cultural milieu was much more stable than it is today.

You want to pair with someone who has what you call "core values" similar to or compatible with your own. Maintaining a relationship requires patience, humility, tolerance, and compromise. A person who can't or won't compromise will struggle to maintain any kind of relationship. Keep in mind that "core values" can change over time too.

Most people could find millions of potential partners who match well enough to form a couple. Think in terms of finding someone who matches close with the qualities you rank as most important and don't worry too much about every detail. And remember that people can change, grow, and compromise in response to new relationships and living situations.

> there should be patterns on this that can be recognized by now based on human life histories

A large majority of all fiction every written has to do with relationships. You could start there. Shakespeare alone could keep you busy for a year. Classics get called that for a reason -- they show us universal human characteristics that we recognize across cultures and time.

You can find plenty of non-fiction as well, from serious books about relationships to YouTube videos from pickup artists. I would ignore all of that because either the authors want to sell something or get you to join a group, or they have over-analyzed something that comes down to feelings and mutual emotions.