Ah yes, the classic "throw subordinates at the mc so that he can get stronger than me when I finally decide to get off my ass". Like, come on. Just go, teleport to a safe distance, use your superior demon lord senses and look for him. Then, see if he can be talked to, maybe take a different a form (not a female lest you will end up in his non-harem, worst of all not a loli because you bet you're 2000 year old ass will end up calling him onii-chan~~by the end of the day) and talk with him. If you can make a deal assume original form and make an alliance, if not then fight him, you will probably be anihilated because of MC OP-ness but not in 5 seconds maybe a good 5 minutes.
Still, loved that the MC actually minds his wife and doesn't leave that fact unsaid. Which is refreshing.