I feel a little messed up.

My husband has two kids (ages 13 & 15) from one woman and another kid (age 9) from a different woman. And currently expecting our own.  

A little background on the first 2 kids. I get along with them although the 15 year old is a little sassy and at times I can come off as if I'm annoyed with her. My husband has noticed this but he understands me because he knows exactly how she is with me. I'm never rude to her nor neglect her ever.  13 year old boy is extremely cool with me and I'm cool with him too. They stay with us part time, meaning, one week with their mom and the other week with my husband and I. My husband calls them when their with their mom and I sometimes tell him to tell them I said hi or I talk to them real quick. A hi and goodbye conversation. 

Now, the 9 year old little girl is a sweet angel but extremely spoiled. My husband will go off on his other kids if they talk to her in any way or don't want to play with her because she's only with us every other weekend. I am against this because I'm sure his other kids feel some type of way although they are used to it. I get along with the 9 year old. I have no problem with her but I have noticed that I'm not really too close to her. In the beginning she would always talk to me, say hi and hug me and I would talk on the phone with her when she was away with her mom. But she stopped trying to talk to me or being close with me, BUT NEVER DISRESPECTS ME. I just thought maybe she was in her own world. Every time my husband would talk to her on the phone he would tell her I said hi even if I didn't and I would sometimes go out of my way to say hi as well and talk to her real quick. My husband also stopped telling her that I said hi and now doesn't even bother telling me to talk to her. I find it odd. I'm not sure if he's waiting for me to say something and for communication to come out of me. I just hate how he spoils her so much. I understand she's the youngest but I'm also having a daughter and we're yet to buy stuff for her. I have seen him lately looking for stuff online though so I can't deny that. Anyway, sometimes I get jealous of how much he spoils his daughter because for one, she's already 9 and second he has other kids. He will literally treat everyone like shit if they tell the little girl anything he does not like.

 One time, we had no car and decided to request an uber to drop off the 9 year old with her mother. When the uber driver arrived, we realized that he only had a three seater in the back and it was 4 of us. I told my husband I'd stay and his kids and him could take his daughter home. He said no so I though how sweet bc he didn't want to leave me behind. Anyway, I requested another uber but this time requested a bigger car so all of us could fit. It said 15 minutes away which we were trying to avoid any delays bc the my husband and his ex have a set time due to custody. I then again told my husband I would stay so he wouldn't be late. He then decided to take me in the room and told me to stop saying that in front of his daughter bc she didn't want me thinking I didn't want to come. It really upset me bc I meant no harm with that. I just didn't want his ex giving him shit. He continued by telling me I was going to make his daughter sad and in my mind I thought it was really stupid bc I clearly said I didn't want him being late. The little girl understands, very smart by the way. Anyway, little things started to occur and I started to feel some sort of resent towards my husband for being like that. Now every time he talks to her on the phone I don't even bother saying hi. I'm sure it bothers him but he's never told me anything. 

So my thing here is, should I be acting differently ? Or what can I do to make it better? Any thoughts on this?