What To Put In A Marriage Contract? - Holam Law PC br Marriage contracts are also known colloquially in the general community as pre-nuptial agreements or prenups. Marriage contracts in Ontario are often negotiated and put into place before marriage, but can also be finalized after the marriage has already taken place. In fact, if your circumstances change at any time during your marriage, it may be a good idea to review any existing marriage contract to consider if more reasonable, up-dated terms are warranted.