OP, what I have learned in a long marriage is that yes it is work, especially to stay through the low times. However, it is also hugely rewarding, so there is work, as it you don't cut and run at the first row, but there is also understanding and love. There are many times though that the hard work is too much (as in if your DH cheats on you or is violent etc) and I would say not worth it. However, the normal work of a marriage is just that, two people making a life together and no couple is 100% suited to each other as we are all individuals with our own quirks.
My second life learning is delete facebook - you will be so much more content. I deleted it two years ago after giving up for Lent (an Irish catholic 7 week time before Easter where we do something difficult) and have never looked back. Facebook is not real (that's what my DC parrot to me about Instagram and the same is true for Facebook).