I think you answered your own question. He was happy the last time he got laid. No wonder he's cranky now, it's been 33 years.

Testosterone therapy and an antidepressant. You would be surprised how a 5 mg of androgel can change an aging man. The antidepressant is a little trickier. They are many. I tried several, but citalopram was the one that had the least side effects for me. He may not need an antidepressant using androgel. Do your research. Good luck

33 years ago! First, I congratulate on you two. You should give yourself a pat on the shoulder too. In 33 years, our body, hormones, looks change. Our attitude, personality, views can change too from experiences. I’m sure you changed somewhat at least.
What can you do? Just let him be.

Massage his prostate and make sure he's got plenty of ammo to keep those punks off the front lawn

Bio identical hormones maybe ?
Sleep apnea makes a person cranky
Does he snore ?
Nutritional deficiencies ?
I recommend this book
The Mood Cure

He can say the same about you- maybe he's cranky because you are a pain. A little introspection before pointing fingers is always good

He's in his 60's?

Wait until he dies.

Schmuck to saint in under 10 seconds.

Sorry but please don’t advise anyone to use any pharmaceutical products unless they’ve been thoroughly diagnosed by a qualified practitioner. Androgen is not something that should be used lightly! This is a drug that is ONLY recommended in specific cases when a man had been properly diagnosed. It can be very dangerous if used incorrectly. Normal aging for men is not a recognized reason to use any type of testosterone products. If any man is experiencing the usual life effects of getting older, there are countless online articles and information to assist with that transition. Men experience normal aging issues just like women do! It’s okay to acknowledge that, and any man who is lucky enough to go through it with a loving partner is definitely ahead of the game.

Sometimes people just want to be cranky. They feel it's easier than being upbeat or happy. For them, positivity = effort. Maybe he's OK with how he is. If you aren't though, that's for you to decide what you want or need to do. Put up with his demeanour or not. The fact that you love him has nothing to do with it really. People love people all the time, and still have to walk away for their own wellbeing.

By the way, checking out testosterone levels would be a decent starting point if he's even into investigating things. Also, adrenal fatigue in men is very, very common. It's a leading cause of man-boobs too by the way, although often GPs don't recognize that. He needs a good Osteopath, but he's gotta be willing.

look what you've turned him into after 33 years.