Then move onto non-work-affiliated groups
Remember, you do need to take things slow and be sure there aren’t any red flags or clear indicators things won’t work out before you establish any real dates. You’ve gotten to know your crush out of work, but now you need to test if he actually wants to be affiliated in any way non-work-related (because before, you went out for drinks with co-workers). Simply do this by inviting him to an event or party where nobody else from work will be. Now he knows he’s special.