What's in Kathy's mind?

Every evening hubby and I share the duty on taking care the two girls. Usually I'd have Sarah and hubby cares for Kathy. This Wednesday night I happend to have time to take care Kathy before she went to sleep, while hubby went downstairs working on something.
After read several stories to her and played with her for a while, Kathy seemed still not sleepy. I put her on her back and read my book next to her. Kathy sucked her fingers for only several seconds, then turned to me and spoke "ah ah ah oh...". So I smiled back at her, and said, "it's time to sleep, my little baby." She'd smile back at me, turn back on her back and continue sucking fingers. After not even one minute, she turned to her side and tried to grab my arm. "ah ah ah oh.......". I pick up her and held her in my arms. Kathy looked around, acting like she was trying to find something. I offered her bottle and she refused. While I was holding her, she kept looking aroung and talking "ah ah ah oh oh...". At that moment, I realized that Kathy was looking for her Daddy. It was about 10 o'clock. Kathy need to go to sleep. I put her in her crib while telling her that Daddy was downstairs doing something important. Kathy seemed to understand me and stop talking. She then took the bottle and went to sleep.
Downstairs I told hubby what Kathy acted. He went on silence for couple seconds, and said, "she's a very sweet baby." After finishing up what we need to do downstairs, we went up to our bedroom. There Kathy was sound sleep. Hubby bent down to the clib and talked to his little sweet girl. "Kathy, Daddy is here. Daddy will stay with you every night from now on." In the bathroom, I was almost in tears.