The Doctor's Little Secret

I've been married to my wife for twelve years now. She's a nurse at the local hospital and we have two kids together who are six and eight respectively. What I'm about to tell you would probably be considered an oddity, but it's something that's brought immense joy into both our lives over the past three years since she introduced me to her DDLG lifestyle. When my wife first approached me with this idea around the time of our anniversary, she had been struggling with personal insecurities and seeking emotional support beyond what I was providing. Initially skeptical but willing to try anything that might help us strengthen our marriage, we started out slowly. She wanted to explore the dynamics where I'd take on a role as her Daddy while she assumed the role of my little girl. It felt strange at first, especially when we decided to bring some playful elements into our relationship, like addressing each other in terms like 'Daddy' and 'Little', or having specific rules that mirrored the childhood innocence she craved. I've always been a bit of an authoritarian figure, even in my professional life as a doctor. My leadership style is assertive yet empathetic. Transitioning to being her Daddy was surprisingly natural for me; it's allowed me to give guidance and set boundaries within our relationship with a level of care that felt deeply intimate. We've grown incredibly close this way, intimate in ways I never imagined, playing pretend but very much real to both of us. But the thing is, we're not just role-playing at home; she often asks me questions or shares her thoughts about what makes for a good Daddy figure during our nightly chats after our kids are asleep. As she's grown more comfortable and confident in this dynamic, my wife has even shared that it helps her feel more secure outside of the house. She says pretending to be 'Little' at home allows her to let go of any stress or anxieties she might have accumulated during the day when dealing with difficult patients. So here's where I need some guidance from you all: Is this something that is considered normal in relationships? Should I continue providing a safe space for her as 'Daddy'? Am I overstepping professional boundaries by having these conversations, despite them being personal and private?