Together or Convenience

Lately I’ve been meeting a lot of men that say they are single yet still living with their ex or a female. I don’t get it. If you’re not with them then why still live with them? Why not have female guest over? Is it out of respect? Is it because it is expensive living in the Bay Area? I’d honestly like to know because I have a male best friend and we can live together and I wouldn’t care if he brought females over. To each its own? Is that a deal breaker for you ladies?