Wow, when my wife (GF then) moved in with me, I didn't charge her rent because

[theking]

..I've been paying and would continue to pay the same amount for mortgage with or without her so I've never asked her for rent. In the case below, I think they should go their own way because I can see more troubles in the future for them  :

My boyfriend demands I pay half of his $600K mortgage and utilities, or go live in a camper van. He says, 'You'll never own this house'. 'He wants me to pay half the mortgage, half the utilities, etc., approximately, $2,300 per month. I am refusing to play ...

[DuMa]

Keyword is "friend" 

keep kissing "friends" and investment or ownership separately.  People tends to break up  more than they divorce by the way   

Still though, even if Im married.  I'm not making her pay for anything.  If she wants to then more love to it.  Not mandatory but if you got the good spirit in you, you would know what to do.