Can my spouse lock me out of our home while we are working out the divorce?
No, she legally may not lock you out of your matrimonial home. Neither spouse can lock the other out of the home they shared as spouses unless and only if there is a court order requiring it (e.g., a protective order barring you from the house), or after disposition of the home is determined in the divorce. Moreover, one owner (whether a spouse or not) can't lock the other owner out without a court order; you both have equal rights to use, enter, occupy, live in, etc. the home.
There are two separate, independent reasons why your spouse cannot lock you out of your home while you are “working out the divorce.” Either reason, by itself, would be good enough to prevent this; together, they represent an absolute bar on evicting a spouse.
First, the law states that one spouse cannot kick the other one out of the marital home (the residence they share as spouses), regardless of ownership—i.e., even if the home is titled solely in Spouse 1’s name, Spouse 1 cannot kick Spouse 2 out of “their” home. Rendering your spouse homeless, refusing to share your home with him or her—this goes against the very concept of “marriage” in our society. Allowing it would also impose a cost on society: the cost to care for (e.g., subsidized housing or shelters) homeless spouses unable in many cases (e.g., in the case of a “homemaker”) to support him- or herself. This cost would be unfair to impose on the taxpayers—why should they, and not Spouse 1, pay the cost of housing Spouse 2? So for these reasons, while the spouses are married, one spouse cannot evict or lock-out the other spouse from the marital home.
This can—and in fact almost certainly will—change after the divorce. The purpose of a divorce is to separate the now-former spouses, both legally and practically: they will not be required to live together or to share a home. However, the law will make sure that both have a home, or at least have a reasonable chance at one. The court will determine if one spouse gets the home and, if so, which one it is. (Generally, it will be the one getting primary custody of any children, if there are any, to avoid displacing the children from their family home.) The other spouse will no longer reside there but will make his or her home elsewhere. The court could also order that the home be sold and the proceeds divided between the spouses, so that both can now seek someplace new to live.
Second, most commonly, when spouses own real estate, they own it together or jointly—usually as what’s called “joint tenants” (though it could also be as what’s known as “tenants in common”). If that is the case, they are both owners of the property; and the law is very clear that one owner cannot lock the other owner out or otherwise exclude them from the access, use, possession, etc. of the property. So long as you are both on the title, neither one of you could lock the other one out. (Also: neither one of you could sell the property without the consent or agreement of the other, unless there was a court order for a sale. If the property is sold the two owners will split the proceeds or profits, after first paying any costs of sale and paying off any liens or mortgages.)