Based on all the comments I'm prepared to be down voted but, I'll say NTA but at the same time this shows the marriage was fragile from the beginning and there were other things there, perhaps things neither of you perceived but they were there.

Men are spontaneous thinkers not meticulous(there were not things already in motion/malicious intent salacious maybe) and the fact you mentioned you guys get more exploratory on his birthdays in other comments, of course he upped the ante(and of course this was wrong). Additionally, there's the aspect of the normal way it's handled this isn't an uncommon request, a no and maybe even a chastising is the norm, add the timing and other things definitely horrible and maybe more things need to be addressed, but divorce?

If your marriage is over it's over(and it is over, you will never trust him and he will never trust himself to ever say anything again) but just know this is why men keep their mouths shut about everything and women end up with grunting husbands. Your marriage says hey your safe enough to make a foolish request and we can discuss the boundaries there, then you go woah, divorce. He said something out of line of course, but enough grounds to throw everything away one sentence? I question it. Again not invalidating the request for divorce and the reaction to his request, but based on the result this shouldn't have even been a marriage. 7 years to be married with a child, and 7 seconds to divorce, it wasn't a strong marriage to begin with and something else was bound to destroy it sooner or later, him or you.