Sorry to hear that Laura. It really is heartbreaking. Addiction buries us and in the process it buries our relationships too.
There is a way out. Getting clean and building a new sober life will help. Be careful because that “addict voice” is still in the background and after a few days (maybe weeks) when the paint of the breakup isn’t as sharp you will hear her: “oh one will feel good, we can pick it up on the way home”. That’s a lie and you know it 
Be prepared for that and start really making a change, to your habits and to your routine. Try a meeting - it’s a great place to learn and to meet people who will help! There’s AA, SMART recovery, and so many other good programs. Find one you like:
There’s lots of good stuff online too:
Remember: the only thing you can control is you, today. The past is the past and the future hasn’t happened yet. Your life is you, making your choices today. Don’t give up - you can do it 