So sorry. If you're determined to divorce your wife, if counseling wouldn't help, and if she is a fence sitter (wants to keep contact with the affair partner and stay married and living with you), here's some advice:
Contact the Bar Association for a referral to a Family Law specialist - one who specializes in child custody issues. Before your interview, surf the web for Divorce sites, and get info about the questions to ask your lawyer. Interview at least 4 lawyers before hiring one.
If yours is a no-fault state, her affair won't come into it, so don't waste time collecting proof. Yes, I know it is the affair that makes your marriage unbearable, but you only have so much time, energy, and money.
Organize your life so that your kids get your undivided attention while they are awake. It is too easy to ignore them when our lives go into chaos. They need you to be strong and to put them first.
Does their school have a before/after school program? If not, you need to look into good, licensed child care. If they need to be driven back & forth, you can check out local universities and colleges for students looking for part time jobs. Check the students out carefully of course. Maybe you can find one who is an early childhood education major, and they can have supervision for their homework.
Since you fear that your wife will take the kids if she goes to MIL, get all the paperwork done about you getting full custody. Does MIL live out of state? If so, papers should say neither party can take kids across state lines without other parent giving written permission.
<small>[ November 09, 2004, 10:01 AM: Message edited by: Bellevue ]</small>