There are so many things that'll be liberating for you.
For example, even with the heatwave I bet you've been limiting when you've been naked/just in underwear around him. Bring on naked star fishing with the fan on, knowing you are totally safe.
Knowing if you need to take strong medicine you can, without balancing the risk of him using your sleepiness to rape you.
You'll (eventually) sleep better as your subconscious will finally get rest. In time I expect your migraines to be milder or go.
No being woken up (or not 😬) from him in the night demanding sex, means you will sleep for longer. You might feel more rested.
No longer walking on eggshells and managing the children's behaviour to avoid his outbursts.
The house will be calmer, less stressful etc.
Even aside from the obvious, you not being abused, there are likely so many restrictions you place.on yourself due to necessity and survival. It'll be hard, but also a journey of self discovery.
If you go through with leaving, and stay away, you'll never have to put up with what you have the last few days, again. Ever. That's liberating.
Best of luck.