I really enjoyed Attached: The New Science of Adult Attachment and How It Can Help You Find and Keep Love by Levine and Heller [0].

The description of the “types” (avoidant, secure, anxious) was very eye-opening, especially while scoring your own “traits” / tendencies / “patterns” for each type. You sorta know what it means when you answer “very likely” to many questions that point to the same type.

As far as I understand, the book is based on this same Attachment theory — it’s a lighter read / introduction to it, but still very good to get the point across. (I didn’t find it as useful to help deal with / compensate for the non-secure type’s thought patterns — not as much as David Burns’ wonderful Feeling Good, for instance)

[0] https://www.amazon.ca/Attached-Science-Attachment-Find-Keep/...

1) Learning about Attachment Theory was a breakthrough; it explains everything about my behavior, relationships, and life choices. It also suggests a method for change and ongoing personal development. Here are some books on Attachment Theory:

Attached https://www.amazon.com/Attached-Science-Adult-Attachment-You...

A General Theory of Love https://www.amazon.com/General-Theory-Love-Thomas-Lewis/dp/0...

Attachment Disturbances in Adults: Treatment for Comprehensive Repair [academic/professional text] https://www.amazon.com/Attachment-Disturbances-Adults-Treatm...

2) It's harder to make friends as you get older. Most friendships are built on an ongoing shared experience that is challenging, such as being in school together. Most of my adult-onset friendships are a result of having worked in small startup companies that were struggling to survive. Casual meetings of potential friends are much less likely to generate the energy and commitment for developing a friendship. If you're interested in the research on this, look into the work of Robin Dunbar, e.g.,

Friends: Understanding the Power of our Most Important Relationships https://www.amazon.com/Friends-Robin-Dunbar/dp/1408711737/

It's much worse than the article suggests. The article doesn't explain why people don't marry. People who marry before middle-age often have secure attachment styles. The dating pool from middle age on consists primarily of people with insecure attachment styles. Relationships with insecurely attached people are especially problematic. If you're not married, but want to be, look for widows or widowers with secure attachment styles, and work on developing secure attachment.

https://www.amazon.com/Attached-Science-Adult-Attachment-You...

https://www.amazon.com/Attachment-Disturbances-Adults-Treatm...