I guess I don't have any advice as I am in the process of leaving the alcoholic. Mine are 3 and 4 and I don't know what to say to them, so I will be watching this thread. I was playing with my 4 year old today with her doll house and like pretending daddy lived in a different house and mommy lived with you. I said, mommy and daddy fight alot and we both love you etc..poor thing was like "well, can't you just not fight?" It always amazes me how much we don't think they pick up on or understand, but they really do!
I think what you said is good, you got to keep it simple when they are little
Hang in there!