Squirel,
Stay strong! Marriage is one of the hardest things in life sometimes. As Frontier said, we don't know the partic problems in your marriage, but try everything under the sun to work it out for the kids. But if you get along better not living together, seperation may be the best alternitive. Don't fight in front of the kids, take deep breath's, and remember your kids are the best parts of you and your wife.
Divorce can get ugly. Depending on what type of person she is, hopefully it can be handled in a calm manner.
Try couples counceling, talking about issues that bother you both better,(I have found it best to say something like, I feel this or that. Not, you do this or that.
Go away together for some quality time. Find someone to watch the kids.
Today it is so much easier to give up rather than working through the issues. Keep your head up and try to leave issues about work out of the marriage, along with finances and such.
Open up to her calmly and hopefully she will do you the same courtecy.
Re-enforce to the kids how much you love them!
I'm not a marraige councler, but I've been around the block a time or two, and these suggestions worked for me.
Keep your chin up! I hope it all works out!