This is going to be fairly useless to the OP, sorry!
I've married twice, at ages 20 and 41. I'm not trying to extrapolate my experience to others, just claim my own anecdotes and conclusions.
At age 20, I didn't know myself. I didn't know what made me happy. I had unrealistic expectations in that regard. I thought simply being married meant that my wife and I were aligned on simple but important things: Who does what chores, long-term goals, how much to spend versus save, etc. My wife and I discussed none of this when dating, and that was my second biggest mistake. My biggest was in not seeing that we were fundamentally incompatible in some keys ways that ultimately broke the relationship.
But I don't want to dwell on the past. When I married Lizmonster, it was a different experience in every possible way. I understood this time the difference between petty differences and the things that "feed" me. Spouse's idea of "neat" is different than mine? Petty stuff, ignorable. Affection? Trust? Honest, respectful dialogue rather than hurtful passive-aggression? Those feed me.
Here's what I do if spouse hangs my shirts the "wrong" way (not saying she does, but this is how I'd handle it):
1) Say "Hey, thanks for hanging my shirts! Much appreciated!"
2) Either suppress my obsession to have them hung the "right" way, or when she's not looking, rehang them the way I prefer.
Easy. Petty stuff. Ignorable.
Also, we talked about life goals when we were still dating. Was being married a goal, or a deal-breaker for either of us? Did we want children? (I already had two, so this meant, did I want more?) What did money mean to each other? (I told her I thought of money as "freedom" -- a means to reach goals like retirement, buying a house, being able to pay bills during job loss, etc.)
An observer probably would've thought we were heartless corporate entities negotiating a merger
but we'd both had bad relationships, and still carried the baggage from those, and I felt too old & tired to be discovering shitty mismatches down the road if they were going to be hard to live with.
Regards the "honeymoon" phase. It's a term we all use, but what does it mean? Does it mean, still get heart flutters every time I see her? Still want to hold her hand, and kiss her? Still enjoy spending time with her? Tell her every day that I love her? If so, I'm still there! Yay!
One difference: When we were still dating, and living apart, I'd invite her over for a nice homecooked meal. For the first months it was: sex first, food after. Eventually it became, do you mind if we eat first? then sex.
Was
that the Honeymoon Meridian?
Maybe, if you want to define it that way.
My question for the OP is, what does your plot want of your married protagonists? Are they going to live more/less happily within your book? Or are they doomed?
If doomed, I'd be most invested in the story if they are fundamentally okay people, just bad together. Some pairings of good people don't work. A marriage can fail with neither person being a villain.