Well,I'll have to check out the book sometime.
It is possible that some of the founding members had wives,and after settling their affairs
left their wives and family to form the group.
Also, some of these various orders of knight-monks had also female members, who took vows as nuns and lived in community.A good example is the Teutonic Knights, who still exist as a religious order of priests,brothers and nuns.Also, the Knights of Malta have a convent of sisters belonging to the order on the island of Malta.It's possible the Templars did have some nuns of the order.However, if so, little if anything has ever been mentioned about them ,in any books I have seen on the Templars.Certainly would be very interesting if true.
When the order was disolved, I assume the nuns, if any, might have been joined to other communities like the Augustians, Benedictines, etc.