Yes, that's planned! In future updates, booty calls and escorts will eventually be open to marriage if you treat them well enough.
I stumbled upon this, a few days ago as I was surfing reddit. If you are doing multiple wives, can you make a restriction that the first wife must have done at least three movies or tv shows with the second person you want to marry? And relationship with the first wife must be 100 and with the second and more wives would raise the dating bar by 2 points. Meaning, at current code, you can start dating at approximately 75. You can marry at about 90. If you want to date a new person, your relationship with her should be at 77. You can only marry her after your relationship with her reaches 92, and she has done a few films with the first wife. This may be fantasy, but little realism can work even in stories like this. If you can't implement this, I won't mind at all, but thank you for taking your time to read through this.