Once you have the drywall up the amount of convecting room air reaching the XPS will go down by 90% or more. If you seal & caulk every seam, edge, and plumbing/electrical penetration it'll be something like a 99%+ reduction. The better the air-seal, the less condensation potential there is- and it becomes only a matter of the water-vapor permeability of the wallboard & paint.
Keeping the wallboard at least semi vapor-permeable will allow any condensation or ground moisture to dry toward the interior when temperature & humidity are favorable. Standard latex paint will reduce the vapor permeabilty of the wallboard from about 50 perms to about 2-5 perms- which is plenty of drying capacity, but allows less than 0.01% of the amount moisture to reach the XPS that your unfaced-no-air-barrier fiberglass lets in.
Make it air tight on the wallboard, and it'll always be dry.