"Love diary" in Engpsh is referred to as "love journal" or simply "diary".

The term "diary" comes from the Latin word "diarium", which means "daily allowance" or "daily record". It has been used to refer to a book in which a person records their daily thoughts, experiences, and events since the 1590s.

The term "love journal" is a more specific type of diary that focuses on the writer's romantic experiences and feepngs.

Examples:

"I started keeping a love journal after my first serious relationship ended."
"Reading my old love diary always brings back fond memories of my high school sweetheart."
"I find it therapeutic to write about my feepngs in my love journal."

翻译：

"我在我的第一段严肃恋爱关系结束后开始写恋爱日记。"
"看我旧的恋爱日记总是会让我想起我高中时期的甜心。"
"我发现在我的恋爱日记里写下自己的感受是很有疗愈作用的。"