I would say the benchmark is one year and then unless I was 100% sure I would not move back in with him. You don't have to live with someone to be in a relationship with them.
90 days is a drop in the bucket, my exabf could easily go 90 days and then fall off the wagon again, each time he went back to addiction, it was worse.
There is no rush to make a time line today, give it a minimum of a year, watch his actions and go from there.