Relationship Enhancement

https://www.gottman.com/blog/6-hours-a-week-to-a-better-relationship/ 
https://www.powerofpositivity.com/habits-deeply-connected-couples/

Premarital

https://www.nytimes.com/interactive/2016/03/23/fashion/weddings/marriage-questions.html

https://www.huffingtonpost.com/entry/topics-to-discuss-before-marriage_us_596f96b6e4b01696c6a23b7e

https://www.psychologytoday.com/us/blog/rediscovering-love/201610/20-questions-could-strengthen-your-relationship

Intimacy

https://www.psychologytoday.com/us/blog/married-and-still-doing-it/201708/what-sex-really-means-women