HI everyone - I joined this site a couple of months ago and have read questions/comments but have yet to post. I have found many of your questions/comments helpful to my situation and can also understand many of your concerns.

Sorry if this is long, however I feel the need to throw it all out there.
My ex and I have been separated 4 years and divorced for 3 years; My fiance has been divorced 2 years.

I have a 9 year old boy (for further understanding - he is on the autism spectrum - high functioning and was diagnosed with Disruptive Mood Disregulation disorder (this is a fairly new label as kids used to be misdiagnosed with childhood bi-polar). I mention all of this as I feel it's necessary to understand background when answering posts, etc. He can be one of the sweetest kids ever and then can be one of the most challenging kids ever - and it can change from hour to hour.

I have a 6 year old daughter. It seems her brother has been mad at her from her birth basically just for being born (both kids see a therapist to deal with their individual issues - and have for years (my son since he was 3 and my daughter once she was old enough to speak her thoughts and needed to vent her frustrations of a brother constantly nagging at her).

My fiance has a 6 year old daughter (just three weeks older than my daughter). She was raised as an only child however she has two sisters from her moms first marriage who are in their 20's. (I say only child as really her sisters were more of caregivers to her than siblings - she never had competition for attention from a sibling). She's very sweet and gets along with both of my kids and is understanding of my sons special needs.

My kids were introduced to my fiance a few months after we started dating - approximately 2 years ago. My son has been all for it from the beginning and my daughter had a few issues at first worrying that her "mommy time" would get taken away. My fiance, then boyfriend, from time to time would take my son for a couple of hours so my daughter and I could have special time and then took my daughter a couple of times so she could get to know him better.

A year into our relationship I was able to be around his daughter (in their divorce paperwork neither could introduce their daughter to a significant other for 12 months from the divorce). We took it slow - I'd go to their house for a couple of hours once or twice a week for dinner or to hang out. After a couple of months we started hanging out with my kids involved too - all 5 of us. We'd get together one weekend day or some weekday evenings. I wanted to take her for an hour or two for bonding time - just the two of us - but she was never into leaving her dad for any amount of time.

So, there's our history as I felt it was important to show it wasn't like we jumped right into blending the family - we made sure it was a slow transition for all of the kids.

6 weeks ago we all moved into one home.

Here are some examples of my concerns............ if my fiance compliments my daughter his daughter will have a meltdown "but daddy, why wouldn't you tell me I looked pretty, you only told her, don't I look pretty?" If I am sitting next to her dad she will immediately come over and either get in between us or sit on his lap and say, in a baby voice, "my dada". I pick her up on Tuesdays from her sitter and many days she'll say over and over in a baby voice, "Me want to see dada. When will me see dada?"
A few weekends ago we had music playing outside and both girls were dancing. His daughter came in crying hysterically b/c it was 'her turn' to dance and didn't want to dance at the same time.

It's not as if she has to ask for attention - he's over the top "Hi sweetie - how was your day?" (plays with her, talks to her, etc) He calls her every morning and evening when she is with her mom. Thursdays are his nights too and they have their night where they will go to dinner by themselves or go to the park, etc.

He's usually very complimentary and loving towards me however when she is around it's so much more low key - kisses on the cheek hello rather than on the lips and rather than 'honey/sweetie' I am called by my name. I don't know if he is different because of the way she reacts and doesn't want to upset her or if she is possessive like this because he's always given her the #1 spot and always will.

I don't want to sound harsh - this is new to all three of the kids and I want to be understanding and compassionate through this. I just am not sure how to handle this - is it just a transition thing? Is it something I need to wait out? How do I say to her dad that her near constant baby talk when addressing him is like nails on a chalkboard? In your experience - if you've had one similar - what's the best way to address this?