He told me he cheated

We’ve been together 4years. And have a 2yro daughter. Last year we had a rough patch where we were both unhappy and broke up. He got offered a job in another state and we decided to make it work so he went there to find us a place to live along with his buddy who was running the whole business. When they were out there they had a drunken night where my SO claims he was blacking in and out and when they went back to the the bar two girls approached them and took them to their room. He woke up with a lot of regret and was scared to tell me. It’s been over a year since it happened and he finally confessed to me last night and said it’s the worst mistake he’s ever made and he’s been scared to tell me because he is scared I’m gonna leave....idk what to do, things have been great this past year....and right now one second I hate him and the next I love him and can’t imagine life without him....he said he never talked to her again, he doesn’t know who she is....I asked him why and he said he had a lot to drink...that mixed with us having problems, his buddy pressuring him and the situation itself........he no longer speaks to this buddy and no longer drinks since that night

Any advice? Anyone who’s been in this situation?