Good job figuring it out in one year, not 5 or 20!
It’s not easy to break up. But he can’t stop you from doing so. He doesn’t have such power. Sure working together is a cumbersome arrangement but still he can’t keep you from breaking up. You don’t live together so don’t go there and don’t allow him to come over. Don’t meet him anywhere. Don’t call and don’t talk on the phone. Is it easy? No, break ups never are. But if one person wants to end it, they can regardless how the other person feels about it.
I am confused on you saying he is sober. You said he drinks and smokes pot. That’s not sober. What do you mean