Some schools want both father and mother of the child to be present at the time of interaction/admission, failing which they do not admit the child. So you should check with the schools in which you want to admit our son and get clear about their expectation on this.
There are schools which allow leave up to 1 year for child if parents are temporarily shifting to foreign shore for work purpose, provided school fee for that period is fully paid. You need to talk to the school management for this.
You may also join your hubby and get your son admitted when you come back. To decide on this, you should have prior information about the number of seats in those schools in LKG and higher classes. If seats are greater in higher classes than LKG then you won't be facing much problem to admit your son when you come back. Some schools only take students at Nursery/LKG/Prep (whatever is their lowest class) an do not take students afterward till class X. Be clear on this for your intended schools.
Hope this will help you to some extent to take your decision.
Wish your son a great future!!