"余下的岁月里" can be translated into English as "in the remaining years of my/one's life" or more succinctly as "for the rest of my/one's life", depending on the context and desired emphasis.
"In the remaining years of my life" emphasizes the specific, numbered years that are left.
"For the rest of my life" is a more general and commonly used expression, implying the duration from now until the end of one's life, without necessarily specifying the number of years.
For example:
"I want to travel the world in the remaining years of my life."（我想在余下的岁月里环游世界。）
"I plan to focus on my family for the rest of my life."（我计划在余下的岁月里专注于我的家庭。）