>>54407352>I'm assuming it's not only sexual feelings, yes?It used to be expected that your spouse was your best friend too. You'd confide in them, share your interests with them, and experience life together. One of the great inventions of the 17th century was marrying for love rather than out of necessity. Maria Theresa, ruler of Austria-Hungary, married her sweetheart and mourned his passing every day until her death. They were so madly in love and so compatible that they ended up being some of the most procreative rulers in human history, with their daughters going on to marry into several royal families, most famously the Bourbon dynasty right before the French Revolution. The 18th century saw a general increase in the prosperity of the regular folk, and marrying for love became an expected practice. Some time in the late 20th century, though, marriage became less about love and more about carnal desires, and when you no longer felt the "spark" of love, you would divorce and move on.
Relationships take effort, even if you and your spouse are perfect matches for each other. Inevitably your intense feelings will fade, and if you didn't build a solid relationship in the background, you won't have anything in common left to keep you together. A relationship is something you have to want to keep together and work to smooth over your differences.