According to a YouGov survey, many relationships lose a lot of the initial affection, partially because most couples stop saying "I love you" to each other [via Mic].
YouGov asked 2,071 British adults about the quality of their relationships, with 959 respondents reporting that they are currently married and 494 respondents that they are in a relationship.

Given that the beginning of relationships are often filled with "I love you more!" "No, I love you more!" types of interactions, it's no great surprise that the study found that people in newer relationships tend to be more expressive — about 50 percent of respondents who have been in relationships for two to five years tell their partner "I love you" every day. The sad thing is that once couples had been dating for more than 10 years, only 33 percent still said "I love you" every day, and that number went all the way down to 18 percent when people had been together for more than 50 years.
So the point is, if you love someone, say it! We cannot let love die, people!