I'm sorry for the new sitch. Probably telling the kids as little as possible. Tell them right now you both are having problems in your relationship and dad is going to be living in a different place right now so that each of you can try to resolve what's happening. You don't know what is going to happen in the future, but to definitely understand that it has nothing to do with them and both of you love them deeply and will always be there for them.
It's probably all going to depend on their age. I told my 3 year old nothing except that he was staying at a friends, even when my H was gone half the time. My 8 year old, that was another story. H wasn't much a part of his first 4 years since we lived in seperate states, so it was easy for me to really let our feelings go and talk about what was happening. We would pray every night for his dad and I'm not sure that I did the right thing by telling him his dad wanted to leave me, but their R between each other hasn't changed. In fact, now that my H came back, he's been more a part of his life. Now had my H NOT come back, I'm not sure what would have happened then. It could have totally backfired, but I felt he was old enough to understand what was happening and deserved to know what was happening.
hope this helps just a little. I will pray tonight for God to give you the right words to say.
Me 33 H 34 S9 S3 M 6 yrs (2gether 11 yrs) EA/PA 1/2006 DB 5/2006 H wants D 6/2006 H wants ME 8/2006 H "said" PA/EA over 8/2006 H erased OW off phone! 2/2007
"It is far better 2 choose humility & change oneself, than 2 wait in vain trying 2 chang someone else."