A decades-old betrayal continues to affect a woman's ability to trust, according to a recent Dear Abby column. The woman, identified as 'Still Matters in North Carolina,' wrote to the advice columnist after discovering in her teenage years that her older sister, 'Daisy,' was involved with her boyfriend.

When the letter writer was 16 and her sister Daisy was 18, she learned that Daisy and her 18-year-old boyfriend, 'Tyler,' were in a sexual relationship. The writer ended her relationship with Tyler. She recalled that Daisy later asked for permission to date Tyler, a question the writer found disingenuous given their prior involvement. The writer and Tyler remained friends over the years, but the experience had a lasting impact.

"It took years for me to learn to trust again," the letter writer stated. When she eventually asked Daisy why she had engaged in the relationship, Daisy reportedly responded, "because she could." The writer noted that while she and her sister generally enjoy each other's company, the past betrayal remains a sensitive subject.

Dear Abby, whose real name is Jeanne Phillips, responded that both Daisy and Tyler had betrayed Still Matters. "What they did showed a distinct lack of character on both their parts," Phillips wrote. She advised the letter writer that Daisy's lack of remorse and her dismissive explanation indicated continued selfishness and insensitivity.

The column also addressed a separate issue from another reader, 'Sis Interrupted,' who was struggling with her sister's husband interrupting their phone calls. The advice given in that case was to apologize for the silence, initiate communication, and attempt to find a mutually agreeable time for calls, or decide if the interruptions were dealbreakers for the sibling relationship.