It is quite a rollercoaster. I was getting better until I found out about her infidelity last week. And you're right, this is the most painful emotional experience of my life--I certainly hope it doesn't get worse.
My advice is, if you're feeling anger and rage (I did), let it out somehow. Go someplace private and let it out, and don't stop until there's nothing left. Unfortunately, it tends to refill, so you'll probably need to purge many times over the next few weeks, but don't let it eat you up inside. It wants to come out, so let it.
I had the fun of knowing ahead of time that my W was planning her trip to see OM, then waiting for the weeks to go by, then having her drop off kids so she could go, then knowing she was with him, her calling the kids while there, then having her return and pick up the kids. Talk about anger!
Hang in, just like the others here, I will also tell you, it gets better. I only have a little anger now and then about it. Mostly now I'm just sad over the whole mess. I also struggle with the hope trap.