Flatlining

I am beginning to feel (in the last year particularly) that I am beginning to want more out of life, and he has slowed down. I feel ready to explore, grow, try new things and think about going to some different places with the family.

I suggest doing that exploring, growing, trying new things, and going different places by yourself.
It does not have to be with the family or as a family, or even as a couple.

Don't suggest to him that he comes to X with you, ask him to mind the children because you are going, either alone or with a friend.

Also, make sure you have lots of time for self-care, time for your beauty routine, some fresh make-up, and some new clothes if the budget will stretch.

There are two outcomes here:
You becoming a more independent person who looks after herself will be attractive to him and the marriage will revive.
Or
The marriage is dying, in which case it is a good strategy to have a life for yourself with your own interests and strong friendships.

Aside from the marriage, you talk about your career flatlining - that is common, particularly now that the economy has frozen up.
Take the long view. Check your pension statements, mortgage statement and savings accounts, work out how many decades or years of work you have left, and make a financial plan and career plan. Do you want to re-train?
That will stop the feeling of just drifting through life.

Is this about your relationship or about life? Nothing changes if nothing changes. I don’t think you can expect to do the same thing for 20 years and still expect everything to feel as exciting as it was 20 years ago.

What new exciting things are you doing in your life? I’m a bit different as I have cancer that prevents me from doing a lot of the things I planned in my 40s, but before that, I decided to retrain for a new career after 20 years in the same industry. Got bored and decided that my passions could be better fulfilled doing something new. What about travel or a new hobby? I bought a horse at 40 and got back into riding after 25 years away. I started hiking regularly and I’ve done lots of hiking holidays (without Dh as someone needs to stay home with the dc). I walked a Camino. Dh and I have some projects around the house, gardening and building works we are doing/would like to do.

Obviously, some of these things take money, but you can find things you love that don’t. You have to keep chasing things that give you joy if you don’t want it to be completely boring and static, but that won’t just land in your lap. You have to plan it and go after it. It also gives Dh and I lots to talk about. He has hobbies and interests, currently training for a marathon after getting into running. He travels too. He rehabbed a little camping trailer over the winter and now we go off on camping weekends with the kids. You gotta kinda find your own fun in a way. This definitely isn’t it, unless you want it to be.

Hi OP I am in very similar boat. Been with DH for 30 years. It’s just ‘meh’ I do love him and I know he loves me, our DC are older so I’m hoping things either change when they move out or we both have the courage to call it a day. It’s so hard as it’s just so boring. We still have sex. But the conversations are the same, he repeats himself over and over and I’m sure I do things that drive him mad too. We’re just so connected financially plus I don’t want to blow up adult DCs lives when we’re so close to them moving on anyway (5 years max). But having said that I do feel like life is passing me by. I’m not sure what the answer is.