Swimming Longer Less Often Vs. Swimming Shorter More Often

Hi everyone, I would like to get your opinions on this. I live in the country in Montana, and during cold-weather months can only get to the pool twice-to-four-times a month. When I told my wife I was planning on swimming once every other week for 3 hours each time, she said it would be better for my body to swim every week for 1.5 hours each time. Which one of us is right? Happy swimming!