My sister is a lesbian with a long term partner. Love them both do death and got online ordained to perform their marriage ceremony. The fucked up part is that I have been having an affair with my sister’s partner for years. It happens every couple of months or so on average but there have been periods where it was every few days and other times not for six months. It is not just that my sister’s partner occasionally wants a man or a c***. She says she feels completely happy in my arms in bed. She loves my sister, but she says she cannot imagine being happpy without both of us. And while i miss her badly in between our times together, I am on the same page where I am happier with her occasionally than not at all.