"They'll Never Take Her Love From Me" is not a song by Elvis Costello, but by Hank Williams Sr., a legendary country music artist. However, I can still provide you with an explanation of the song's meaning and story. The song speaks about the deep love the narrator has for a woman and the regret he feels for breaking her trust. Despite their separation and her being with someone else now, the narrator believes that no one can ever take away his love for her. The lyrics convey a sense of longing and bittersweet nostalgia for the times they spent together, referred to as the "used to be." The narrator acknowledges that someone else may now be holding her in their arms, but he firmly believes that they can never replace the love he has for her. The song also touches upon the narrator's decision to step aside, thinking it would bring happiness to the woman he loves. However, he realizes that her love for him was never going to go away, and even on the day of her marriage to another person, he still believes that they can never take her love away from him. Overall, "They'll Never Take Her Love From Me" explores the profound and lasting impact of love, even in the face of separation and the passing of time.