Here is the sitch, your W and kids are moving into your in-laws so you can stay at the family home and save money on apartment until October. You would like to stay in it until end of Nov because you paid for the mortgage until then.
You and W are in a tug-o-war regarding dates. I see that you have several options and if you can talk about it without flinging mud, these options might be good for kids and everyone else involved.
1) You stay until Oct as suggested by wife - what do you have to lose? Nothing, you save money for rent from June to Oct.
2) You stay until Nov - one extra month of free rent but R suffers with wife. Where will she and kids stay from Oct to Nov?
3) You stay until Nov - but you suggest that the kids stay with you at the family home. Wife can have them three times a week or whatever arrangment. That way kids still get to stay in family home and you get more time bonding with them. Wife can stay at in-laws. If she is the one leaving you, then she should leave the family home, not you. You play hardball but she sees you as more of a powerful figure and not a pushover. RESPECT.
4) You sell the home, split the profits, everything over and done with while the W and kids stay at in-laws.
If she won't have a mature, reasonable discussion with you on this and insists on yelling, screaming or if you guys come to an agreement, then you need to get an intermediary like a lawyer involved.
She thinks she still calls all the shots in this family, e.g. you stay in the house until Oct 5th (without consultation with you). But you need to show her that whether the two of you are married or not, there needs to be discussions on things, especially if these include children. Say it in a loving tone, but do not apologize for wanting a discussion. Weighs the pros and cons in the best interest of the kids, not because you want a power struggle or because you want to her weather the consequences of her decisions.
Don't worry if she gets mad at you or not, she is already mad. And she will stay this way because it enables her to move forward and leave you. She is using this energy to change her life drastically.
You need to see the motivation here and be the bigger person. Refuse the power struggle. Stand up for yourself. Don't get dragged into long winded arguments. Be lovingly detached. Let the whirlwind of her behavior blow over and make sure you don't get sucked in again.
BE there for the children. IF their mother is acting crazy, they need you more than ever to act sane, stable, like a ROCK.
Me:39 H:40 S:9 D:7 First Bomb ONS:June 07 Second Bomb OW: March 08 Separated: March 08 M:15 yrs T:18 yrs H deep into A with OW Achieved ACCEPTANCE May 30, 09