I felt that I had to respond to this!
Op, you are living the exact same life as my mum did. My Dad got very overweight and lazy, and just didn't want to do anything except stay at home. It worsened massively when he retired.
He just stopped taking her out and they stopped going on holiday. He was also sleeping far too much - taking multiple naps in the day and flaking out at 9pm (he is a heavy drinker).
She stayed with him, and they just became passing ships, because their sleep schedules were not aligned. My Mum became very lonely - at night time she would go on to her computer and play solitaire whilst he snored away in another room.
If she had been with another man, her retirement could have been wonderful. In fact, my DH's father and his partner (who are 74 & 68) are living the life I wish she could have had - they are just back from touring India, and are booked to go to the far east next month, and at some point they're going on a Safari. My Mum would have loved all that (it was her dream to go to India), but instead she lived out her days with a husband who was permanently asleep in the arm chair, with his mouth gaping open.
Sadly, she died a 2 years ago, and we moved Dad in to a retirement village (at his request). He has now seemingly "come to life". He has a mobility scooter and there is an on site bar where he drinks copious amounts of alcohol most nights with his new friends, before zipping back up to his apartment to pass out. I'm glad he's happy, but it's bittersweet when I think of how my Mum spent her retirement doing nothing.
Me and DH are now in our 50's, and both determined not to fall into a pattern like theirs. We take regular long haul holidays. We don't really have hobbies, but we do watch TV together every night and binge watch box sets and we go out for dinner/cinema etc.
I think in your shoes, I would just start booking stuff and see if you can pep him up. If funds allow, I'd book a holiday abroad. Even if it's just a lazy beach holiday - there's a lot to be said for lazing in the sun, and then having dinner and wine at night, followed by dancing. Start there and see if you can muster up some enthusiasm. Has to be worth a try after 30 years.
But if he just won't budge, it might be time to think about how you really want to live out the next 30 years. Life is short, you don't want to spend the rest of yours rooted to the sofa. 