I haven't played in a while, so let me know if I missed something. I'm playing as Aragon and made Naples stay under the union. I got Portugal through a Union CB via missions and then got Castile. Soon after my leader died and Portugal broke its union (figures). They had no allies until the month before the truce was up then got Brittany (who got Burgundian Inheritance), France, and England. I fought the war with my subjects and allies (Austria, Milan, Papacy). We won the war after I got France out of it. Then, a few months later, a loyal 190 relations Naples breaks the union without a leader death and with no truce or anything. I just declared Restoration CB and got them back. Easy fix, but confusing situation.