If everyone cared more about the problems of being married why would they bother to marry at all. Marriage isn't all problems and nothing else.
Nick was about sacrifice the whole world over his loved ones. It was his mother and aunt who talked him down (Trubel had failed) from putting his love and need for his family (and friends) over being a Grimm. So clearly Nick didn't always put being a Grimm above everything else. His family was important to him, with Adalind he got to have both without compromise. Unfortunately with Juliette, it was like being forced to choose and no amount of denial/revisionist rhetoric changes that both Nick AND Juliette (much to her dislike) chose the Grimm. It wasn't Nick alone who made that decision. Juliette made her choice as well.
Nick was about sacrifice the whole world over his loved ones. It was his mother and aunt who talked him down (Trubel had failed) from putting his love and need for his family (and friends) over being a Grimm. So clearly Nick didn't always put being a Grimm above everything else. His family was important to him, with Adalind he got to have both without compromise. Unfortunately with Juliette, it was like being forced to choose and no amount of denial/revisionist rhetoric changes that both Nick AND Juliette (much to her dislike) chose the Grimm. It wasn't Nick alone who made that decision. Juliette made her choice as well.