When we say "marriage is hard" we mean to encourage. We mean to empathize, to validate, to normalize the struggles that can so often happen in marriage.
But I want you to know that there's a major negative impact of saying this so unquestioningly. 
Make sure you listen this week as I pull in thought work to understand why the phrase "marriage is hard" can be one of the biggest disservices we do for one another and for ourselves, and why I think we should all chuck this well-intentioned phrase right out of our collective vocabulary.