This happens quite a bit. My uncle had a girlfriend for decades while married. When his marriage ended, he briefly dated the gf but eventually was single again. I thought about the gf who waited for him and I felt for her, she basically died alone. As far as the neighbor, some people don't want to be alone to the point that they will sacrifice their pride, standards and morals to have someone. I'm pretty sure your neighbor was at best getting 50% of the story from the boyfriend. Good read!