I'm 41, my husband is 43. We've been together for 20 years, married for 11. We don't have kids, through choice.
I love my husband. He's a good man. We met young and have grown up together and been through every up and down through life together. He adores me. Luckily, we still find eachother just as attractive now as we did when we met!
So that's the "soft" stuff.
When it comes to the practicalities, it's honestly felt like a slog at times. As the type A personality, the higher achiever, and higher earner, I've spent my life nagging, encouraging and cajoling my husband into being and doing more. More housework, more career progression, more saving, more DIY, more healthy eating...
Alone, I would have lived in a smaller home (I barely own anything, and he has loads of stuff), paid off the mortgage by now, have tonnes in savings, keep the place immaculate with barely any effort, eat really simple and healthy meals, and live a pared-back, peaceful lifestyle - and wouldn't have spent so much energy bringing someone else along for the ride.
He's wonderful and I love him and think we'll be together forever. I want his companionship when we're old. But I can't honestly say I'd advise a 20 year old to bother.