We go to school and teachers teach us to read and write but nobody teaches us about the purposeful commitment and intentionality it takes to make our marriages healthy and sustain love over a lifetime. Most people seem to think love should "naturally" sustain itself as it did during the beginning of our relationship with each other -but that just isn't realistic.
The fact that you're having disagreements with each other isn't a problem -that just shows that there are some areas of your relationship that need to be worked on. And that's normal. People are different, so of course you're going to run into times where your differences come out and rub each other the wrong way. But what's important is that you both commit to work on those differences until both of you are satisfied. When you do that, you're walking the right road together and over the long-run you'll do just fine.
If either person isn't 100% committed to scale every mountain that comes before you to make your relationship work then you aren't ready to enter into it. That's part of the reason the divorce rate is so high. People are entering into the commitment they're making without having the strength of character, fortitude, and resolve to keep the promises they're making to each other and also to God. God cares VERY MUCH that we keep our marital promises -He enters into the marriage with you whenever you marry so your promises aren't only to each other but also to Him.
Now is the time to learn how to argue constructively before you have children.
When we resent someone in some way we need to "be on the alert" that even innocent gestures on their part can become suspect to us. Even something as simple as their walking into a room or whispering something to someone else can be conjured up in our minds, to look to us as if they're doing it on purpose to irritate us -as if they're involved in some diabolical plot to hurt us further. What they may be doing may have no connection to their past actions that hurt us in the first place but our resentful feelings against them can often taint our perception of what's really taking place.
Sometimes people hurt us unintentionally. We may view that they've hurt us intentionally and want revenge. But sometimes when we really look back again, we can see that they weren't intentional in trying to hurt us. That's when we need to confess our judgment of them and forgive them for their unintentional hurts committed against us.