Why isn't my boyfriend trying very hard to have a relationship with my daughter?

Okay, I have been with him for quite a while now & we have a great relationship for the most part. I have a four year old daughter, I had her in high school. I broke up with my child's father when I was pregnant because that 2 year relationship was just a mess. That boy was my first kiss, first everything & things became more obsessive and way crazy. Anyways, I waited over three years before I even kissed another guy. Now my bf who love to death is practically living with me. Every night he's there after work & leaves to work the next morning. We do things with my daughter a lot (but also have our alone time).He gets along great with her, and cuddles with her. They seem to have a good relationship(i don't know what you'd call it). I'm not asking for him to take over fatherhood or anything at all!! I don't want him to feel burdened by this. But if you date me, you date my daughter too! They do love each other, she asks for him all the time! Well today he has the day off (he works A LOT, usually gets one day a week), and we woke up & I was getting ready for work when usually he takes his day off when i'm off. So my daughter wanted to go to the festival and I was like oh you and cynthia (my roommate) can go take her! He said he was just going to go home and chill with his friend. I kind of got offended and sad like you have never actually spent the day with her, wouldn't that be fun? We started bickering about it and in the midst of it all he said "she's not MY kid!" Well now i'm at work & he went home but came back. Now he's with my daughter & bestfriend doing exactly what he said he didn't want to do. What happened? Is he hesitant to keep progressing in our relationship? Does he not want to give my daughter the wrong idea? I mean she knows who her real dad is even though he isn't around. He also likes to remind me from time to time that we don't live together even though he showers every day and sleeps every night at my place, & even slips up & calls it "our place" sometimes he even slips & calls me his "wife"...lol flattering & i love it. But why does he have to always make things "clear"?