This is an unofficial version of a Massachusetts General Law.
Section 2-301
(a) If a testator's surviving spouse married the testator after the testator executed a will, the surviving spouse is entitled to receive, as an intestate share, no less than the value of the share of the estate the spouse would have received if the testator had died intestate as to that portion of the testator's estate, if any, that neither is devised to a child of the testator who is born before the testator married the surviving spouse and who is not a child of the surviving spouse nor is devised to a descendant of such a child or passes under section 2-603 or 2-604 to such a child or to a descendant of such a child, unless:
(1) it appears from the will that the will was made in contemplation of the testator's marriage to the surviving spouse;
(2) the will expresses the intention that it is to be effective notwithstanding any subsequent marriage; or
(3) the testator provided for the spouse by transfer outside the will and any intent that the transfer be in lieu of a testamentary provision is shown by the testator's statements or is reasonably inferred from the amount of the transfer or other evidence.
(b) In satisfying the share provided by this section, devises made by the will to the testator's surviving spouse, if any, are applied first, and other devises, other than a devise to a child of the testator who was born before the testator married the surviving spouse and who is not a child of the surviving spouse or a devise or substitute gift under section 2-603 or 2-604 to a descendant of such a child, abate as provided in section 3-902.