It was after I quit drinking and my SO refused to that I realized what a f'd up relationship I had been in all this time. He is no longer my SO, is still drinking daily to excess and doesn't understand why I won't give us another chance.
It can be very depressing. It can be very lonely. And little by little, as you discover who you are outside of a toxic relationship, you will start to feel better. Some people feel better instantly, it's taken a while for me. But toxic is no good, no matter how you look at it.