To avoid situations where guild leaders just leave the game and never return to hand over leadership, there is an inbuilt code where leadership is handed over after a period of inactivity from that character. If the person who became leader after you is inactive for a certain number of days (you can check this in the guild tab), the leadership will be handed on again.
If you and your wife were absent for a particular reason, you could explain it to this member (via in-game mail, etc) and hopefully they will be compliant and hand leadership back. Customer service can't force a player to give up leadership, then again not all players want to stay guild leader and they could happily hand it back. Hopefully the situation can be resolved just by mailing the person and checking their activity in the guild tab. If not, it may be best to start a new one (I know this can be difficult given investments such as decos, guild ship, etc) or find another guild that suits your style.