Connected with marriage or the relationship between two married people, especially their sexual relationship. (Cambridge Dictionary)
Of or relating to the married state or to married persons and their relations: Connubial. (Merriam – Webster)
Conjugal means relating to marriage or a married couple’s relationship, especially their sexual relationship. (Collins Dictionary)
Example
The 5 Secrets to Be Happy in Conjugal Life.

https://www.thebeginnersyoga.com/5-secrets-to-be-happy-in-conjugal-life/