May-December romance refers to a romantic pairing where one person is significantly older than the other. The age difference is at least a decade, but often more. The phrase comes from the younger person being in the "spring" of his or her life (i.e., May), while the older partner is in his or her "winter" (i.e., December).
“忘年恋”指年龄相差很大的两个人之间的恋爱关系。这里的年龄差距至少要有十岁，通常都多于十岁。用May-December romance这个短语来表示“忘年恋”大概是表示这段浪漫关系中年轻的一方处于生命的“春天”（即“五月”），而年长的那一方则可能处于生命的“冬季”（即“十二月”）。
May-December relationships are pretty common throughout history. British royalty often paired up differently aged partners based on family trees and political needs. Even modern arranged marriages can have a large age difference within the couple.
从历史上来说，“忘年恋”的现象并不少见。英国王室经常会根据家族发展或政治需求而使年龄相差很大的两个人联姻。现代的包办婚姻中也有很多年龄差距很大的夫妇。
These days, the politically correct term seems to be "age-gap relationships," and they're not just for movie stars.
如今，用政治上比较正确的词语来表达“忘年恋”的话应该叫做age-gap relationships，而且这样的事情并不只发生在电影明星身上。