My money says she will come and do the cruise but head back to BMs the day after she and your DH return. Enjoy the time to yourself!

Oh how I wish parents would go back to the basics. Kids do what they are told when they are told. PERIOD! DOT!

If they don't like it, they can move out at 18 and finish growing up on their own time and their own dime.

I got too big for my skivvies when I was 16 and informed my parents that I would not go to the Military School they selected for my second sophomore year of HS.  As soon I dropped those words, my dad reached into his brief case, wrote me a check for $500 and told me to write to my mother when I found a job and somewhere to live. Since I was 16 I did not have to go to school so, I was on my own.

Before they called for his flight to board I had returned the check and "agreed" to go to the Military School.  

My first sophomore year of HS was at a school of my choice.  A near zero oversight liberal arts school.  I became an avid rock climber, spelunker, alpine skiier, discovered the mystery of young ladies, and that vagrants will buy underage kids anything they want from the liquor store for a bottle of their choice and a few $, and managed to pass only a single class that year.

Where and when I grew up, school only went through 9th grade for Expat kids so we all went to boarding school or were sent to live with relatives for HS.

I am eternally grateful to my parents for parenting and keeping me from continually shoving my head up my own butt as a young man with a chronic case of the teen boy brain farts.