Thanks. My own were 20, 18, 14 and 11 at the time. What to tell them as an intensely personal of a topic as you'll find around here. I personally decided to tell my two adult daughters the truth, and later told my older son the truth as well (in an age-appropriate manner). I decided that I wanted my kids to know that at least ONE parent would ALWAYS tell them the truth.
I would talk to a good family therapist about this before deciding. Exposure is NOT advocated in DB, but nor would I lie to my kids if they asked me a direct question. Something to think and pray about, for sure.
25mlc will, I'm sure, give you 10,000 words on the opposing viewpoint, lol (j/k 25!!!)