Explaining parentage to a 4 year old

On Friday I was sitting at my parents with Jesse and I was asking him about colours, his favorite food etc and among everything I asked him was what is your name baby and he answered Jesse and then his brothers' surname so I corrected him and said no baby your surname is...., he looked incredibly puzzled and proceeded to ask me why his brothers had a different surname to him... eish guys I wasn't prepared to have to explain this especially not to a 4 year old, but it brought to home how astute and aware even a young child can be.

So I proceeded to tell him that his brothers daddy is Uncle (name) and that we had loved each other and I had his brothers because of that love but that after a time we decided  that it would be best for us to not be together anymore, and then a time later I met his (Jesse's daddy), we loved each other very much so we then got married and had him, and that we were so lucky to have him.. he listened with great intensity smiled and then said ok and ran off obviously satisfied if not bemused by my awkward attempt at answering his question in an age appropriate manner.

I know kids can often say the most amusing things but I don't think I ever even thought about parentage or whether someone was a half or full sibling or whether their parents were married or not... ever... until I was in my teens at least, I have often wondered though as a parent how my having being married twice and having 2 fathers between my kids would if ever affect my children and this question answer session albeit brief gave me a good insight and train of thought for this matter.  In short my kids are no less loved and just because our relationship did not work does not mean either of us failed or are bad people, life happens and it did and here we stand.

I would love to know what if anything your child has ever said or asked that has left you at a loss for words or at a loss of how to handle the situation, ie questions regarding the birds and the bees... that one is hard guys nothing can prepare you I tell you, I am dreading the talk with Jesse, we have already had the talk with Loghan and Gabriel which was the mother of all awkward but we got through it, I don't think I am quite prepared for Jesse and his ever challenging mind though, with my luck he will wait until we are in a crowded room for of people and will ask me at the top of his lungs as the room falls dead silent =)