I think I am a little perplexed as to why this seems to be hard for you to understand and I do not mean any disrespect- but asking about someone's failed marriage isnt a good top\ic for most any conversation. I dont even know if its limited to the fact that it's your boss, its just one of those topics that-unless you are good friends or familiar with someone- should be off limits. And its also private. What if it was a woman and she divorced because she was physically abused? I would guess that could possibly trigger her or at least make her feel embarrassment.