Sorry to hear you are going through this. My parents have separated after 30 years together about 6 months ago after my dad decided it was an awesome idea to start serial cheating on her... ANYWAY... The emotions etc you are going through at the moment I totally understand - I never thought "it" would happen to us etc...
My DD is only 14 months old so I didnt have to explain anything to her - I am still sad though because he doesnt seem to want anything to do with her and poor old mum is stuck in limbo while theyre trying to sort everything out. She was always a SAHM with us kids and so was faced with the rest of her life with no career/income...
Tough times, big hugs xxx