The Boundaries of Caregiving

I've been a caregiver for my partner since they became ill last year. They're in their late 30s too and we've been together for almost ten years, but this sudden shift has really thrown me off balance. I feel like there's something...off about the dynamic now that I'm handling all of their needs, meals, medication, personal care, everything. It started innocently enough. My partner asked if they could call me 'Mommy' while they're sick because it made them feel better and less alone when I was around to help. It was endearing at first, but as time went on, the line between our roles blurred significantly. Now, they want more control over these moments, asking for timeouts when upset, wanting guidance in decision-making that isn't medical or practical. The intimacy of it feels different now, and I'm unsure if this is just a side effect of being ill or if there's something deeper here that needs addressing. Yesterday, we had an argument where they seemed to regress further emotionally, lashing out with words like 'You're not taking care of me properly,' even though objectively nothing was wrong. I feel lost in all of this. Is it normal for a caregiver to sometimes step into these other roles? Am I being too sensitive by feeling the need to draw hard lines around what's healthy and appropriate? The boundary between supporting my partner as an adult and indulging their desires seems very thin now. Any advice or insight you have would be deeply appreciated.