.

slap him. maybe it will refresh his brain

He's not mad because you did it, he's actually mad because you did it without his consent.

He's the man and ought to have given you the go ahead.

Let his anger die down, then ask for forgiveness.

Peace would reign after you acknowledging him as the man with your plea.

Wow.. I think he should have been made aware of it before you embarked on it. That must have been his anger.
Nonetheless, he's your man. You know if it's best to tackle it now or later if he cools off. It has to be apologies and accepting wrongs. Even if it was in your plans, one of you isn't comfortable with the process so some gentle voice and explanation from one or both sides should do the trick.
But I don't know if announcing that he's on Nairaland is a good idea o. It should be an internal issue.
Two wrongs don't make a right. Men can get irrational over even insignificant issues, I think it's an ego thing. But some submissive docility can do the trick. Good Luck!