After a lot of great advice from really great people, I have come to a decision. For those of you who haven't been following my sitch here's a quick summary.
My W decided to get an apartment in October 2008. At first, I agreed that we would shift back and forth to minimize impact on our kids, but at the last minute I just couldn't do it and told her I was staying in the house and she would be at the apartment, and the kids would stay at home. She threatened to go to court to have kids go back and forth, so I conceded that they could shift without any legal action.
For 3 months we did that, and then in January, I decided that it was in fact best for the kids to have one home, so I told W that we could do the shifting back and forth. I saw what an effect it had on their schoolwork, organization and social lives, and really, having them shift back and forth was detrimental to them, and they are at such a pivotal time in their lives, I had to put what is best for them first and foremost. I also thought getting her back in the house, at least part of the time, was a pathway toward reconciliation. It's now been 4 1/2 months since the "nesting" and we are no closer to reconciliation, perhaps further apart.
I've decided that I will be moving home on Fathers Day, June 21, two days before school ends for them (last two days are fun days anyhow, as all grades are submitted June 19). Giving them the summer to adjust to the next change is better than doing it now, plus I can't think of a more fitting day to do it