I have been 12 months with my first dishwasher. It's a slimline one put in our very small kitchen and to get it the freezer had to go.
No regrets at all - we only filled the freezer up with things that we forgot about and ended up chucking.
There are 4 of us, we cook fresh everyday and the slimline usually goes on once a day.
We used to wash up at least twice a day so it def saves water.
As we are on a combi boiler it saves running the tap till the water gets hot.
But the best bit for me is that you get without those piles of stuff around the sink all the time - the pile of stuff waiting to be washed, the pile of stuff waiting to be put away, usually both piles at the same time...
And now dp can't do his very annoying thing of filling the sink with dirty dishes that you have to lift out and drain before you can start washing up.
You finish with a cup, bowl, meal's worth of crocks, and you just put them in the dishwasher. Then when its full (usually after tea for us) you switch it on.
I would never go back to having a freezer if it meant losing my dishwasher.
Get one, or buy your dh some marigolds as he will be needing them.