A Mommy's Secret Guilt

I've been playing the role of Mommy for years now, but I never really thought about what that means until recently. My partner, who is twenty years my junior, calls me 'Mom' and treats me with all the respect a child shows their parent. It started as a game, but over time, it became something more meaningful to both of us. The problem is, I love him like he's really mine. I worry about his future, I discipline him when he screws up, and I comfort him when he cries. But now that my son has left for college, I've started feeling this gnawing guilt in the back of my mind. It’s as if I'm betraying my own child by caring so much for someone else's. We do everything together; bedtime stories, morning coffee at the kitchen table like we're starting a new school year. We watch cartoons and have movie nights where he sits on my lap like when he was little, not that he ever was, but sometimes it feels like it in those moments. And there’s nothing wrong with that...right? He’s an adult now, too. The guilt doesn’t come from the kink or what we do under the sheets; those parts are consensual and understood by both of us as healthy play. It's this constant questioning if I’m fulfilling my role in his life the right way, am I doing enough for him? Am I doing more than is okay? Every time he calls me 'Mom' or says, 'Thanks Mom,' I feel like maybe it’s not just a game anymore. Maybe he needs something from me that no one else can give. But how do you tell someone they need to stop calling you what feels so natural and comforting?