What happens to my Contacts when I create a new Apple Account?

I’ve always shared an Apple ID with my wife, however I have been having more and more problems arise lately. From what I understand, many (if not all) of these problems are related to sharing an Apple ID. For example, my wife’s photo showing up on people’s phone when I call them from my phone. My question is: If I create my own Apple ID, and start using that on my phone instead of sharing with her, what things will I lose? What happens to all the contacts? What about calendar events? She creates calendar events, and I can just pull up the calendar and see them now. Will I lose that ability? I guess I’m just concerned that if I get my own Apple ID, I’d lose a bunch of things and have to start over!

We currently share the same Apple ID on each of our phones, as well as 2 iPads and a MacBook. We both use the iPads and MacBook, but obviously each use our own phones. Would I only need to use my own Apple ID for my phone since we share all other devices? And keep the other devices on the same Apple ID that they currently use? Any help is appreciated!

[Re-Titled by Moderator]