Yeah it started in Chapter 2 when you decide who to call to set up your apartment to come home.
You can call Jen or Georgina but the other one gets left in the cold. The one you call puts a cam in place and finds out about you and Dee.
Devs might be able to elucidate as to reasoning but it did not seem too crazy to me. You have to call only one person to set up your place and you pick who you like more. Like picking if Elena is going to be with you or not or similar decisions. It did emphasize how Dee is of course the focus as setting up the place for a romantic return with her was important. Calling both your side hos was not....
I did recently play through all the chapters to get ready for chp 4 and you can have all the women until that call.