Maybe think about this: my child goes to school at age 5. Says "I have two mums". All the kids who have never heard of someone having two mums say "NO you CAN'T have two mums". My child gets upset "yes you can, because I do". None of these kids have ever heard of someone having two mums. "Wow, thats weird" they say, "wow, you're weird". Now my child is the weird kid, gets teased. All because some parents think its too hard for them to talk about. But how hard is it going to be for my child if you don't? I'd say A LOT harder than you saying one simple setence in passing every now and then to your kids?