OP, I am glad that your talk went fairly well.
I think you need to go and read this link, so you can see what you're doing to drive her away: Love Busters
She also has bad behavior, but you aren't the one staying away. You have driven her away. She is *really* pissed off at you right now. I am not sure if I've ever seen a pregnant wife leave her husband without infidelity or physical abuse occurring, on any of the boards I read, at any point in my years of reading. Pregnant women want to nest, they are trying to bring their family together.
I agree with jld that your wife has a strong character. She also has a good job, and a strong support system who will help her if she decides to give you that divorce. She has the best possible situation for a young mother who wants to divorce.
If my husband threatened divorce multiple times, then threw tantrums in front of my friends and talked spitefully about leaving me alone on NYE, while I was pregnant? Maybe you'd be alone on NYE, you certainly wouldn't be with me. So I fully understand where she's coming from and why she's staying away.
I disagree with most of the posters who are trying to get you focused on her behavior. She has bad behavior in spades, don't get me wrong. But focusing on her right now will get you divorced, as she is already literally out the door. If you want to stay married, right now you need to continue to clean up your side of the street.
If you aspire to be a grown adult, you need to stop the tantrums. I very strongly suspect that you've thrown tantrums for a long time. If your wife is trying to ignore you by putting on headphones, why are trying to push her by continuing to talk at her? Your wife left you, wouldn't speak to you for days, and when she finally did, you argued with her! Stop trying to force your will on her. You can learn to resolve issues in a much better way.
I am being harsh right now, but it's important that you see that it's not just that last threat of divorce that pushed her out. I am not surprised that she is also immature and not handling things well. Of course not, we tend to seek our own levels. If she handled things more maturely, she would have never tolerated any of your tantrums. If you were more mature, you would never have fought over going out against doctors orders, you simply would have stayed in. You both react to terrible behavior by acting terribly. This has probably been going on for a long time. Your wife finally put a stop to the cycle by moving out. This is an opportunity to fix things and for the two of you to grow together.
I think the link I gave you will help you. You might also check out the Basic Concepts, to learn more about conflict resolution and emotional needs. Right off the bat I can see that your wife needs recreational companionship and financial support. You can learn to negotiate ways for both spouses yo get their needs met. The website goes over the basics, but there are books that in depth and are often recommended: Love Busters is one, His Needs. Her Needs is the other.
It's possible that you will clean up your behavior and she won't change, but it's highly unlikely, in my opinion. She is talking to you; she's pregnant; you have a long history together. Both of you are better together, as long as you both are able to learn better behavior. If you start, she's likely to follow, and even if she doesn't, you'll be better off.
I do hope that you're feeling better. Hopefully you'll get some downtime while she's away and you can get some rest. It will be much easier to move ahead once you feel better.