So sorry for your hurt.
Many of us here have come second choice to the bottle so know how you feel.
There is loads of support here for you.
There is only one person you can truly be responsible for in life & that is yourself.
You could not have controlled his drinking or made him sober, that he will have to or not have to find on his own.
If you had of stayed in this relationship then you would have joined the rollercoaster that goes with living with an alcoholic & sometimes the rollercoaster never stops.
You have made the right healthy decision.
Doesn't hurt any less I know so sending a big hug.