The chance of having bipolar with one parent having the disorder is closer to 35% according to the web. It increases if both parents have bipolar.

Of course there is nothing we can do for you except wish you well. If you don't have a therapist you might consider getting one for the family as both you and the kids learn how to deal with their father's illness and the divorce. If you haven't done so yet, change the locks. It is easy to do... just a screwdriver is needed.