I have a friend called Sarah. She is married with two children. She and I have been friends for over 20 years. When I am in the UK we meet 2 or 3 times a year. We usually have lunch then walk in the wild hills of Argyll. Occasionally, I will spend the weekend with her and her family. There has never been any romance between us. We would both be horrified at the thought. She is a sister. She will be part of my family for ever.