Grounds for Exclusive Use
The court isn't likely to bar your spouse from your home without good cause. If you want exclusive use of the property, you must have grounds. The rules can vary somewhat from state to state, but there must generally be such tension and animosity between you that it's unreasonable to expect the two of you to coexist under the same roof. For example, if you don't have children, Oregon requires that there be a threat of domestic violence. If you do have children, it may be enough that the friction between you and your spouse is detrimental to their well-being.
Permission From the Court
You must ask the court for a temporary order, obligating your spouse to move out and giving you exclusive use of the premises. This usually involves filing a pretrial or pendente lite motion. In New York, if you have sufficient documented evidence to prove your case, the court may issue the order on the documents alone, which means the judge will base his decision on your written submission. Documentation might include medical reports if your spouse has hurt you, police reports if you've had to call the authorities for protection, or notarized statements by witnesses who have knowledge of the conditions you're living under. Lacking this evidence, the court will order a hearing to determine what's fair under the circumstances.
If the court awards you exclusive use of the home, this generally doesn't mean you're free to change the locks. It means you have a right to live there alone, undisturbed, during your divorce proceedings. Your spouse still has an ownership interest in the property until the court decides otherwise and directs what will happen with the asset in your final decree. If the court orders your spouse to leave the premises during your divorce, this has no effect on the court's final decision regarding the property, and it does not necessarily mean that you will get the keep the home forever.
Final Disposition of the Property
If you want to keep the home after the divorce, you must typically buy out your spouse's interest. This means compensating him in some way for his share of the equity. If your financial situation is such that you can qualify to refinance the existing mortgage, plus an additional amount representative of your spouse's share, this is one option. You might also be able to relinquish other marital assets equal in value to your spouse's portion of the equity. If you can't qualify for a refinance and if you don't have sufficient other assets to manage an offset of equity, the court can award the home to your spouse or order it sold. The court might also order a sale if both you and your spouse are determined to have the property. In that case, you and your spouse would divide the proceeds.