How do I tell him?

My husband and I have been together since 2012, married 2016 and now have 3 small kiddos. We always had huge problems with his drinking it wasn’t probably until this Easter that he became sober and things have been somewhat better. I feel horrible even typing this here because that’s all I’ve ever wanted, him sober. But now I’m living in fear of him giving in and getting drunk or getting home drunk and starting a fight with me like he would before. I’m not happy anymore. I’ve cried so many nights because I don’t want this relationship anymore I’m living in fear of our past and it breaks my heart because I thought him being sober would fix all our issues. I don’t know how to tell him. He seems so happy he’s always reassuring me he loves me and he’s there for me always. I’m going to break his heart and I’m just so lost 😞