Ooh this is interesting OP!
Me and DH met and got together young, 22 and 24. Been 2 decades together! In terms of attractiveness he's just my "type", IYSWIM? I'd double take at him on the street if he walked past :) so that core "phwoar!" reaction doesn't go... Even yesterday he was cutting the grass and I caught myself watching and thinking isn't he handsome, what a lovely bum, and all that jazz... It hasn't faded!
We did a lot of partying and travelling and sucking the marrow out of life for the first 10 years or so - made a lot of memories, cemented all the things we had in common, built a very solid foundation while we were 'growing up' together.
Then felt ready for kids in our mid 30s and luckily had an easy time with that, we have 2 small kids now. The baby years, sleep deprivation, financial hit, plus Covid made things tough for a while - probably our toughest time. DH had some issues with depression and was self-medicating with too many wines... We talked it over, committed to couple's therapy, spilled our guts to the stranger in the room, got some insights, did some mutual apologising for taking each other a bit for granted. DH was massively out of his comfort zone, but he put the work in because the deep love is there. At the end of the day we both wanted to fight for each other.
We are doing well now and I think we're out the other side of a storm. Maybe it could have sunk us but I truly think he's my soul mate, I'm not perfect myself and have my baggage too, so I don't expect perfection from him. Deep down we have a lot of mutual love and respect and that's the starting point for everything else...
As my kids get older I see him in them, they have his smile and his lovely eyes - I have a lot of gratitude for my kids and to him for giving them to me. Also feel like it's such a gift to make a family with someone you love. I feel like our relationship is definitely changing with time but right now it feels like it gets deeper, not that it fades. Realise I'm lucky, obviously!
Sorry if this sounds boast-y or lecture-y; I don't mean it that way, just wanted to share. :)