I feel MORE than qualified to comment on this thread - DH is a farmer and I am a teacher. He works ridiculous hours compared to me. Last week, like the OP's DH, he worked something like 110 hours. That is completely normal for him. We've had days off cancelled, arranging a couple of days away is like a military operation, and last night was a good case in point - we went out to the cinema for the first time in god knows how long, had planned to have a meal afterwards, and got a phone call to let us know our sheep had escaped on to the road and we needed to get home to retrieve them. Meal went out of the window and we ended up eating pizza on the sofa at 11pm.
Having said all that, DH wouldn't do my job (Secondary science teacher) for all the tea in China. The stresses of a teacher are very harsh, and they "do" very much need their holidays - most teachers I know are utterly knackered at the end of term. There are stupid and ridiculous amounts of paperwork, 9/10 lessons, you get some sort of attitude from pupils, I am sworn at daily (normal), there are a lack of resources to do your job effectively, and an incompetent arsehole of an education minister who couldn't find his arse with both hands, a torch, a neon sign saying "arse this way", who keeps changing the parameters of teaching. There is no question that they deserve their holidays.
However, I believe that many, many people in all walks of life don't work as hard as farmers. I certainly don't work as hard as DH. I have guaranteed time off, I finish at a reasonable time if I want to, I have time to meet friends, do hobbies, and go to the gym. I have friends who are junior doctors, solicitors & barristers, they work hard, but they still have time to do stuff.
Farming is not a "job", it is a very, very stressful way of life. Made worse by the fact that people want cheap food, but things like farming costs like fuel and fertilizer are rising, while farm gate prices are dropping. We found an old milk-check statement from 1993 - we were getting £0.31p/litre in 1993. Now, we are lucky to get £0.27p/litre with double the costs!
OP, I feel your pain, I really do.