Ok. Here goes. I'm going to say this and it is going to sound horrible to you and to your DD. I don't mean it like that - I mean it to be blunt but well meant advice coming from someone who has been there.
I have 4 children. 2 boys then 2 girls. DD1, who is third on the list, was a very very very difficult baby and then toddler. She had (and continues to have) some health issues that were major when she was small and are now easily managed.
As a toddler she could tantrum and play me and now-xH for fucking Ireland. She did the peeing in the supermarket, peeing the floor, peeing the bed if she didn't get what she wanted. She never slept.
She was incredibly clingy to me and her dad, refused to accept babysitters and howled inconsolably for the whole time we were away. Aged about 2 and a bit a conversation about me and her dad going on a very rare night out
"You go away a leave me I cry a cry a be sick. Then Jo phone and you a daddy come home"
And that went on all day - I cry a cry a be sick.
Jo (aka Joanne) lived next door was 19 and thank fuck was a psychology student.
so when DD1 "cry a cry a be sick" all over the floor, and looked up at Jo grinning from ear to ear and said "I be a sick you phone my mummy a come home" Jo said nope, cleaned it up and sat it out with howling child til we got home.
I let DD1 dominate for an easy life. I organised things to please her, amuse her and I walked on eggshells in case she would have a tantrum, or behave badly. Her tantrums were epic, absolutely epic, could go on all day if I put the wrong sock on first.
She was not quite 4 and I snapped one day when she ordered me to reverse the car out of the car park space I had chosen and put it in a different one as she didnt' like that one, and I turned the car and we went home.
It was hell to sort for a few months but I did sort it and she's now a happy well adjusted popular girl who is doing well in school. She's 13 now. I know there's a mum at school who is a MNetter (I don't know her username) and I know if she read this she would not believe it was my daughter.
I suppose what I am trying to say is, in a very long winded way, you're the parent, she's the child. You have to find some balls and sort her out now and stop her tantrumming and dominating you and your husband and your life and stop her limiting where you can go and what you can do.
It won't be easy, it won't be pleasant, but if you don't sort it now, what's going to happen in 10 years time when she's a teenager? If you can't control her now at 7 you have bucklies of controlling her at 17.