Either a husband or wife may make a will without any obligation on his or her part to provide for the surviving spouse.  To lessen the potential harshness of such a result, Mass. Gen. L. c. 191, §15 grants a surviving spouse the right to waive the provisions of the deceased spouse's will and opt for a statutorily provided share of the spouse's estate.

Prior to the adoption of various amendments to Mass. Gen. L. c. 191, §15, a surviving spouse who waived a will would be entitled to the same proportion of the estate he or she would have been entitled to if the deceased spouse had died intestate.  This is no longer the case.  In fact, in most situations, a surviving spouse who waives a deceased spouse's will receives a lesser percentage of the estate than he or she would have received in the event the spouse died intestate.

For example, assume a husband dies leaving an estate valued at $1,000,000.00.  His will provides that his entire estate is to be distributed to his two children in equal parts and the wife is to receive nothing.  If the wife chooses to waive the will, she will receive $25,000.00 outright, and the income for life on the remaining one-third of the estate after deduction of the $25,000.00 cash payment (i.e., $308,333.33).  Had the husband died intestate, the widow would have received one-half of the husband's estate absolutely.

To exercise a right of waiver, the surviving spouse must file a written instrument waiving his or her interest under the will (if any) and claiming his or her statutory rights under Mass. Gen. L. c. 191, §15 with the probate court within six months from the date of the probate of the will.

There is one significant exception to the right of waiver.  If a court has entered a decree that a spouse has been deserted by the other or is living apart for just cause, the surviving spouse will lose the right to waive the provisions of the deceased spouse's will.  Mass. Gen. L. c. 209, §36.

Although there are certain exceptions for non-beneficial rights conferred to a spouse under a will (e.g., a provision that investments created by the will shall not be changed without the consent of a wife), a spouse who waives a will loses all rights he or she may have been entitled to under the will.  See 1 Belknap, Newhall's Settlement of Estates and Fiduciary Law in Massachusetts, §20:3 (5th ed. 1994).  However, a waiver does not invalidate the rest of the will.  Other legacies will not be affected, except to the extent the entirety of the estate has been diminished by the payout to the surviving spouse.  To the extent someone must bear the loss of the payout, the loss will fall on the residuary legatee unless the terms of the will evidence a contrary intention. Hesseltine v. Partridge, 236 Mass. 77 (1920).