My 29-year-old wife is close to a 22-year-old male colleague she has known for four years. He often sits very close to her, and they attended a dance party together. He has offered to walk her back to her flat and has even tried to plan a holiday with her. But she has assured me he is more interested in her than she is in him. I just find it weird they would be so close, given the age gap and his apparent immaturity.