Well, what else could it be about? It's like 'Dressin Up (Reprise)'. She was clearly having bad sex ("I found I had to love myself the way I want you to love me"), and was sick of bowing to his wishes all the time ("I lost my own identity" "No more questioning, I'll be the one defining who I'm gonna be"), her insecurities obviously led her to create characters in bed to hide behind ("Dominatrix, Librarian"), then obviously there's "Let's go deeper, let's get closer".
I can't think of any other explanation other than she had to take matters into her own hands cause her partner was bad in bed.
