One method that has been shown to help keep passion alive in a relationship is:

Question

Quizplus · Accepted Answer

Doing novel, fun, exciting things together can create new shared experiences and keep the relationship from becoming stale. It can also trigger the release of dopamine and other feel-good hormones, enhancing the feeling of passion in the relationship. Having avoidant goals or frequent arguments can create distance and erode the passion in the relationship, while sharing frustration with your partner can be helpful but is not specifically related to maintaining passion.

One Method That Has Been Shown to Help Keep Passion