How could I prevent breaking up?

It all depends on the circumstance. Sometimes asking to take a little time away from each other or finding common ground can work, as well as being open about needs and being aware of what made you guys want to be together in the first place. Unfortunately, the ending of some relationships are inevitable, though, but as mentioned - depends on the circumstance.

You have to be honest and open about everything (problems/feelings/accomplishments), have good communication skills and respect with each other (by being understanding/loving/supportive), and I would say have fun and continue courting/dating each other. Don't let it be stagnant and in a routine like robots. Change things up and be spontaneous and do things differently. Otherwise when things don't turn out to be how it was initially in the relationship, things change during the course of it such as being complacent, different goals, beliefs, lack of needs not being fulfilled, etc. There's probably more that I'm not mentioning but basically I feel like you have to have a good foundation with each other where you both are on the same page that prevents a breakup. Hope this helps!

It is harder to break up with someone when you don't start the relationship with the option in the equation. We all go into relationships and marriage thinking like well, if it doesn't work out we can always split or divorce. I believe that a relationship will hold strong if you love well, and welcome every part of the other person to the table. Also, if you take the time to read the 5 Love Languages together it will give you a sense of what will make your partner happy and satisfied, with a more likelihood of them wanting to stay.