It sounds obvious, but having someone to support your decisions and help you when you need it is incredibly important
My fiancée is very supportive of me. I am so lucky to have that. She doesn't push me around, make decisions for me or guilt me for things I do. I try my best to do the same for her, and I'm sure sometimes I come up short. We support each other and put a lot of our energy into holding each other up.
We do this because we have just about no one, and I mean no one, in our lives who are actively supportive of us. My family has made fun of my every decision. My mother would tear me down every day about whatever thing I wanted to do, and especially when I changed my major from computers to the arts. "He'll always live with his mother," is something she said often. It tore me apart inside and she never knew it. That part was my fault, but perhaps my own mother should have helped me with my decisions instead of slamming me when she could.
Judi's parents are even worse, though. They not only don't support her, they actively tell her that she's making the wrong choices and decisions. They mock her as being a child and worthless. They are actively negative where my family is more passive (and, in general, much less serious.) She has had to deal with much more than I have with emotional abuse. I've only really recognized this in the last year or so, and only very recently have I put a lot of effort into showing her my support.
I say that this is important because I see, all too much, couples who don't actively support each other. I'm not saying that your support should be blind. If there is an issue with health of you, your partner, or the people around you, that should be a worry. If your partner wants to make a change and you think it's a bad change simply because you don't like it, remember that you not liking it is just as good as them liking it. If you support a decision, some good will come from it eventually. If one of you is right, recognize it.
That's really the thing that hits hard here. It's an idea you should carry everywhere: say when you're right, but also when you're wrong. If you and your partner can be honest with each other this way, your relationship will be really strong. If you treat everyone like this, then you'll probably be a bit happier in life. Everyone makes mistakes, everyone misjudges, and everyone makes something feel more important than it really is.
If you find yourself disagreeing, chances are that you're a jerk. If you're happy being a jerk, then fine. Just don't expect anyone else being happy with you.