When you're getting married, perhaps doing your pre-marriage classes, you will learn there is a huge emphasis on that first year. Apparently, it's when all the knock-down, drag-out fights happen because you're learning to live together, and you're creating and adjusting to a new way of life with your spouse. Although my husband and I had disagreements, we didn't have them explosively. In fact, a lot of what I read/heard just didn't apply to us.
Here's some facts I learned our first year.
1. Satan is an Accuser and he will accuse your spouse to you.
I'm pretty sure this is a direct quote from Jimmy Evans (founder of Marriage Today, a ministry I highly recommend), but man, I learned it the hard way. Once my husband did something (even insignificant things that rubbed me the wrong way), my over-thinking would take over. By the time 24 hours or whatever had passed, I had over-thought myself into a complicated tale which ultimately made my husband the bad guy. I would carry that until we talked about it, and I realized he wasn't the bad guy. He's actually my Prince Charming.
2. Love keeps no record of wrongs. Or dirty dishes. Or socks on the floor.
Let's say my husband left his socks on the floor. Following my experiences from above, Satan would be trying to convince me he did it because he didn't care about me, or some equally untrue garbage that fed my ego or pride, and I would stew around in these thoughts for a couple of days before I decided to bring it up. Then, as you can imagine, not only THESE socks were brought up, but the socks he left LAST WEEK on the floor. Before long I had a laundry list (pun intended) of instances that clearly indicated he didn't care about me. Not only had I kept records, but I had harbored offense in my heart each time.
Let's put it like this: I started with 100% love for my husband. Then, each time he was doing something wrong, he lost a little bit of love. I decided one day that those socks, or dishes, or whatever, were not worth spending the rest of my life only loving my husband 98%. I wanted to love him 100% all the time. I had to make a conscientious decision not to harbor offense towards him every time he did something I didn't like.
3. Relationships have seasons.
The honeymoon period is great, but then the dynamics of the relationship change. Maybe your spouse grows distant, or you didn't quite listen to the advice above and now don't quite love him as much as you used to. Maybe it's in your control to fix, but maybe it isn't. In these times, my mind likes to kick into overtime thinking "is it always going to be like this??"
The answer is no. Relationships have seasons. Just because you feel like you have a terrible marriage today, doesn't mean it won't be great tomorrow. Take all of these energies you're using to overthink & channel them into identifying the situation (this may require talking to your spouse) and coming up with solutions or ways you can help.
Example. My husband went through a season where he was just a little mopey about life in general. (His job, his situation, but nothing to do with me or the kids.) It took him even a long time to admit to me why he was so mopey. Obviously, I can give him advice, but I can't fix it. So I brainstormed some solutions to help him through the season. I helped him talk through it and identify exactly what was causing these feelings & then told him what I could do to help. Eventually he did get un-mopey, but I’m not even sure how much I had to do with it. It was just when he was ready.
4. You will get no sleep.
People's minds always go to the dirtiest places when I say that, but it's not only true for the reasons you're thinking of. (Note I said, not only true.) It's also because -- and this has been confirmed from other married people -- sleeping in the same bed with a person after you've had your own bed for years is just difficult. They move and wake you up. And they will actually hit and/or kick you in their sleep! My husband one time elbowed me in the eye. Not the eye socket or the nose. In the actual eyeball. I have no advice for this, but I don't see this acknowledged enough as a legitimate struggle in marriage.