In February 2014, Bill Goodwin and I coauthored an extensive article on cohabitation which was published in the New Jersey Family Lawyer. 

Here is an excerpt... 
 
Decisional law is an evolutionary process, and  cases addressing post-judgment cohabitation’s impact on alimony obligations are no exception. The purpose of this article is to assist practitioners in deciphering this area of the law as it has evolved over the past 38 years, especially as the cases can appear conflicting at times. This review of cohabitation is especially timely in light of the Appellate Division’s May 7, 2013, decision in Reese v. Weis, which addresses two issues prior case law has not: 1) What constitutes “an economic benefit”; and 2) when does such a benefit warrant termination—rather than modification—of alimony. The goal of this article is to assist practitioners in drafting effective settlement agreements and guiding clients where post-divorce cohabitation is contemplated by the alimony recipient (or suspected by the payor).

http://www.highroadsolution.com/file_uploader2/files/familylawv34n4feb2014.pdf

Bill Goodwin is a senior partner at G&K and manages the family law department.