All relationships entail some degree of power dynamics. If you're in a marriage where things are relatively equal (either you agree on almost every decision or you have consciously agreed that you will each have your departments of decision-making power) then you're not feeling a constant push and pull. But I see a lot couples with power imbalances that can become real relationship killers.
There are different kinds of power imbalances in relationships; the most common are some throw their weight around because they make more money, have a high-profile job, leverage their seniority because of a significant age differential. You can probably recognize at least one of those within your immediate circle of friends or maybe even in your own marriage.
When we think of power, we often think of money.
Money can cause a lot of imbalance in relationships. The one who earns the most can either have a tight-hold on if and how money is spent, and at times even keeping the spouse in the dark about family finances. I can't tell you how many intelligent, accomplished women I have met who have no idea about their family's finances, and most importantly, don't have a say on how money is spent. If you don't know how much money there is and have no say in spending, then overtime you will enter a zone of imprisonment without the actual prison bars. You can't get out or have a say, because you don't know if the prison bars are made out of paper or steal.
Another form of power imbalance can develop when one of you has a high-power job.
While this often goes hand in hand with money, it doesn't always have to. Let's say you have a highly stressful job at a hospital, work in a sector where anything can shift from one moment to the next, you can begin to leverage your professional demands as a way of getting what you want: "I need you to do this now because I don't have time", "I can't talk to you now because I need to attend to 100 work emails", "Do you understand how much stress I'm under! How can you even expect me to go to the kids' soccer tournament?!". Sound familiar? Work can become a wall behind which your partner hides whenever he/she can't or doesn't want to engage with you, and as a way to guilt you into doing what he/she wants you to do NOW!
Significant age differences can play an important role in power dynamics.
When one partner is quite a bit older, there tends to be this aura of patriarchy in the relationship. You know the one, where the husband (yes, usually it tends to be the husband!) claims more say around what the couple does: from how to spend money, where they vacation, to how to structure the marriage, to sex, to plans for the future. I notice it becomes almost an unspoken agreement that the more "senior" spouse will have final say, like the old wise priest at the top of the mountain. But I also see the complete reverse of this as well, especially when a significantly partner enters a relationship with a much much younger woman or man. While the younger partner might not control all aspects of the relationship, he/she tends to get their way by, you guessed it, throwing a tantrum when they things don't go their way. That partner's power comes from her youth and a wider breadth of emotionality. This seemingly infantile behavior is actually just as much of a power holding strategy as money, high-power job, or seniority.
Now these few examples are not to say you are dealing with a real power-person and that your relationship is doomed. If you are able to bring up this imbalance to their attention and they genuinely take it to heart by collaborating with you to find a way to make the marriage more equal, then you have a true opportunity to shift the dynamics positively. This is where couples counseling can help you find a way to a partnership of equals.
WARNING: However, if your partner always invalidates your needs, makes you feel invisible, humiliates you, or does the old bait-and-switch (promising you to change but never actually does anything to change), then I'm afraid you're dealing with a real power-person. There's no balance to be had when you're entrenched with a power-person. You're dealing with someone who views all interactions as a win or lose, and they will make sure that they always win! If that's the case, it's time to re-evaluate your relationship.