The phrase "honeymoon stage" refers to the early and happy period of a relationship or project when everything seems perfect and smooth. Full definition
What about years later — long after that initial honeymoon stage of complete debt freedom? (lifeandmyfinances.com)
I'm still in the totally infatuated honeymoon stage with this one, recommending it to people any chance I get. (criterion.com)
And the sense of excitement and exploration that was once so activated in the beginning of a relationship or so called honeymoon stage, diminishes. (sanfranciscomarriagecenter.com)