Unfortunately the banks are closed at the moment, but in the morning I intend to change the bank details. I justify this by reasoning this will safeguard my home, and so my boys will always have somewhere to come.
Gyn, there is no need to justify your actions to this woman in her current state of run-away-ness. Your only justification is "I have decided that ________," or "It's what I decided," or "I felt this was best for me," or "I did what I felt I needed to do" or something very similar.
Your wife is destroying her marriage, and potentially good-sized pieces of your sons' hearts. YOU are not the one doing this, and YOU don't need to justify your actions to someone who is on this path.