You should confer with an attorney in your area who focuses his/her practice on family law and also mediates or uses collaborative practice. You can hurt your case by moving out of the home, without a written agreement that states what time you will spend with the children and how much time the children spend with your husband. Many states measure the amount of time children spend with each parent by the number of overnights the children spend with each parent. Based on what you are describing, your husband will end up with more overnights. That will make it hard for you to argue for primary custody. You may also be entitled to other assistance from your husband, such as child support, spousal support and property. I suggest you confer with an attorney soon to find out the best way to approach this situation. In most states, if one party wants a divorce, the judge has to grant it. Let an attorney explain ways, using mediation or collaborative practice, where hopefully you can settle your differences but remain civil to each other.
The real issue / concern isn't whether it's "abandonment" in some legal sense (like giving grounds for a divorce), but whether you'd be setting up a "status quo" as to custody that a judge would likely continue if a divorce action is filed. It doesn't sound like a bad way to resolve things (you spending time with them every day, but with them sleeping at old house), but the danger would be that this is what a judge would order should continue until a divorce action is completed. That's always the danger with someone moving out of a marital home.
A better idea would be to wait until there's a written agreement as to custody (and whatever other issues exist), reached either through mediation (with the agreement reviewed by competent counsel) or a court order.
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You should not leave the home and if you do, you will find it difficult to get back in. Instead, file a motion to deal with the issue and ask a judge to have him move out.
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