Reply to comment  It's EASY to adopt an adult, and it isn't
always about a "parent-child" relationship either, just like the
recent news article about the 48-year-old man adopting his
42-year-old girlfriend.  I'm happily married (33+ years now) and
my wife and I have legally adopted our shared and longterm
girlfriend, so she is now an official member of our family.
Plural marriage may not be legal (yet), but this was our way
around it, and now we're all one big happy poly family, and
loving it!  Thanks for all the advice and help along the way!