To start out as a disclaimer, I know divorce sucks. I know kids are hurting. I'm not trying to take her Father away from her, though I do think that it is not asking too much to be allowed to be affectionate and receive affection from my partner.
I have known my stepdaughter since she was 3. In the last 8 months, she has started calling her Father "Dada" and has become way clingy. I know that some regression is normal. I can deal with her feeling jealous of me and I understand that when I am affectionate with her Father she somehow feels left out though she is not.
However...in the last 6 months her need to be the center of everything related to her Father is way out of hand. If ANYBODY in the house is getting attention from her dad, she has to find a way to take that attention away. She has started dirty dancing in front of her 11 and 13 year old stepbrothers (who want nothing to do with it), slapping her butt in front of her father...grinding her private parts on her dad's leg if we are sitting next to each other, jumping on his lap to give a sitting striptease with her chest in his face...flipping her shirt up...She constantly needs to be on her dad's lap and I swear I see her grin and wink at me when I get pushed away from her father when we are near each other. Again, though I don't like THAT part, what has me concerned is the sexual nature of her affection lately. Last time, with the leg grinding, I told her that while I understood she wanted her Father's attention and that we both loved her Father, that I didn't love her Father the same way she did and that it was not appropriate for her to try to mimic our relationship. I don't know if she heard me or not or if that was even the issue.
I'm worried about her. I'm not really sure what to do. I think this is about jealousy but I don't know what precipitated the increase in it or why it has suddenly become sexual. When this happens she is told the behavior is not appropriate either by me or her father or both of us at the same time so we are on the same page. But is this normal? What is a family supposed to do? Is this indicative of something else?