Call TOMORROW and make an appointment with an attorney. You need to file an order for temporary support ASAP. Do not count on your H to "do the right thing" - he won't. Right now he's spending money on HIS new place that may be coming out of YOUR share of community funds. See an attorney and protect your rights.
Too many women stall on this step, hoping that if they don't make waves, the WAS will come home. It's a big mistake. Protect your and your children's financial issues, asap. The attorney can also give you a rough idea of what you can ultimately expect in terms of child support, alimony, etc. You need to start making financial plans now, BEFORE you get behind on the mortgage or in debt.
Call tomorrow. This is the business end of things. Protecting yourself financially will not prevent him from coming home, if he's going to. Financial reality may hit him in the face and make his fairy-tale escape seem a little less attractive. Stand up for yourself and your kids and get what is due to you.