An "anniversary trip" refers to a special vacation or outing that a couple takes to celebrate the anniversary of their marriage or relationship. Full definition
My husband and I finally got away for a long overdue 10 - year anniversary trip (it was a long time after our actual anniversary... because babies). (wellnessmama.com)
We ended up not taking a traditional honeymoon after the wedding due to our work schedules and lack of time off so this will act as a honeymoon / anniversary trip in one. (apieceoftoastblog.com)