Mass. Gen. Laws ch. 208, § 50 – Termination, extension or modification of rehabilitative alimony

(a) Rehabilitative alimony shall terminate upon the remarriage of the recipient, the occurrence of a specific event in the future or the death of either spouse; provided, however, that the court may require the payor to provide reasonable security for payment of sums due to the recipient in the event of the payor's death during the alimony term.
(b) The alimony term for rehabilitative alimony shall be not more than 5 years. Unless the recipient has remarried, the rehabilitative alimony may be extended on a complaint for modification upon a showing of compelling circumstances in the event that:
1. (1) unforeseen events prevent the recipient spouse from being self-supporting at the end of the term with due consideration to the length of the marriage;
2. (2) the court finds that the recipient tried to become self-supporting; and
3. (3) the payor is able to pay without undue burden.
(c) The court may modify the amount of periodic rehabilitative alimony based upon material change of circumstance within the rehabilitative period.