:(

I took a branch off from one side, it was not "crispy" dead and it was hard to cut by hand, and it still looks green in the inside....?

It's dead. I can see a couple of clues as to why.

The "I watered often" might have been a problem. Did you test the soil to see if it needed water? In general, even evergreens don't need to be watered often in winter, and wet, cold soil leads to root rot.

The other problem is cold combined with it being a potted plant. Because a pot is more exposed than a plant in the ground, the soil in a pot freeze more solidly than nearby soil, and will do far more freeze-thaw and this can damage roots. It's generally suggested that potted plants be hardy to 2 zones colder than where they are in order to survive the winter, and the boxwood is already near the edge of its tolerance to be planted in the ground in your area.

If you want boxwoods, they will do best in the ground in your area, or at the very least in a pot that gets moved to a sheltered spot such as against the foundation in a shady area where the pot is surrounded by bagged leaves or in an unheated garage that stays a bit warmer than outdoors.

IME, I've tried cutting the dead stuff and plant keeps getting dried up. I cut sone more, it dries up some more until I've cut the whole thing. I love boxwood and hate it when this happens. but absolutely nothing wrong with going conservative route and cutting as needed. Who knows, in your case it might be enough

In my case my hedgerow developed problems when we had a drought from hell, followed by an above average rainy season. The are easy care but seem to resent extremes.

It probably froze solid at the roots.

:( Ok, my first dead plant. Last year was my first year putting boxwoods in pots, the other 2 are doing great, but they are bigger and the pots are gigant, probably they were better protected from the freezing temperatures :(

Thanks everyone!