Any Italy tips for honeymooners that haven’t been there before?

Hi! We're looking at two weeks, figuring on Rome and one or two other locations. Fiance leans toward Portofino because of Instagram, but I imagine somewhere like Portofino but moreso will do. I want to make sure we get enough relaxing in. I expect Rome will be pretty active, so do you have any tips for where to spend time that might be a charming coastal area that is less frequented by tourists?

Expecting to go next year in August, I know that's the worst time for tourists so out of the way might be ideal.