Whether one party moves out in the immediate, assuming the details will be hashed out over time, or both parties stay put and a battle ensues, dealing with who keeps the marital residence can be stressful, time consuming and expensive.
Whether married or co-habitating, a couple who lives together for more than 30 days, regardless of whether the lease, deed and/or mortgage is in one or both parties' names, both have an interest in the property and cannot simply be ousted.
By law, a person cannot be removed without proper notice and possibly even a formal eviction procedure. This means a party cannot simply change the locks and throw his or her former significant other's belongings on the front lawn.
This is what the law refers to as "self-help," and not only is it illegal, but it is also frowned upon by the court and usually triggers a judge to award the injured party with moving costs or other monetary relief.
If both parties happen to be on the lease other issues may arise. For instance, as most New York residents know the criteria for lease approval is often to show that the parties earn some 40 times the monthly rent. Many times one party is unable to do this alone. One party may be willing to move out, but wants to be taken off of the lease to avoid future liability for the rents, where the managing agent may not allow this.
Similarly, where parties own property together, it is often difficult to get the bank to change the loan documents to one party's name. After all, it is in their best interest to have as many people "on the hook" as possible, in the event of a default.
Often times parties will take drastic measures in insuring their right to the marital residence. One unfortunate technique I've seen in practice is where one party files an Order of Protection, claiming his or her spouse as a potential threat, which limits how and why the parties can contact each other and the distance that they must stay while the court works out the details.
In that interim period, it is often the "victim" who maintains possession, while it is up to the "assailant" to find a place to go.
Once a party is out of the residence it becomes very difficult to get back in. This is why I often advise my clients to stay put, but sometimes that is easier said than done.
One of my more recent clients attempted to co-habitate with his wife until he confirmed that she had been cheating on him. Sharing the space with her became mentally exhausting and unhealthy for him.
In that instance, rather than advising him to leave the residence, I advised that we work with his wife (and wife's counsel) in reaching a settlement that would get her out of the house as quickly and painlessly as possible.
Encouraging the parties to settle will reflect the best interest of the client. In the event that the parties indeed want to "duke it out" in the courtroom, in comes the real estate brokers, appraisers, forced sales and a flurry of other activity that will only be frustrating and costly.