.. is mayonnaise an instrument?
It will be something he will just have to get used to. It'll take a while but eventually he'll stop crying when you leave him and it will become routine.
Start leaving him little by little now.
15 minutes here, 20 minutes there, work up to an hour.
And if he cries, it's okay. It's a process that will take time
Let him see that you ALWAYS come back. It'll be easier than suddenly not seeing you for hours