marriage lite

(名詞) 稱呼未婚同居男女或已依法結婚的同性夫妻的中度貶抑詞。

But the other side of the coin is that a civil partnership is, face it, marriage lite. Terms and conditions apply, if you're gay your results will definitely vary from the bride and groom down the road. Because civil partnerships simply do not come with all of the legal rights of marriage.
—Cahir O'Doherty, "Irish Government introduces gay marriage (lite)," Irish Central, June 26, 2009

They are right about the fact cohabitation — what some call 'marriage lite' — is changing the social map. Census figures show the proportion of adults in de facto relationships more than doubled between 1986 and 2006. With other countries showing similar shifts, many social scientists studying this trend conclude marriage lite is not a change for the better.
—Bettina Arndt, "Shacking up is hard to do: Why Gillard may be leery of the Lodge," Sydney Morning Herald, June 29, 2010