Congratulations, Jen. I couldn't be happier for you two! <3

Shakespeare refers to it somewhere as the "honey-month." Same basic idea.

And yeah, what @1 said.

Venice is a shitty gimmick town. I have never had a worse vacation anywhere. Go to Barcelona instead.

I had read that the "moon " part referred to the fact that the trip was supposed to last a month.

No matter how it's defined, though, the implication is that the initial period of bliss has an expiration date.