What is the usual reason why couples break up?

For me, one good reason would be the lack of communication, judgment, expectation, opinion and need each one has for each other. Lack of constant openness to certain needs and continually seeking so much expectation or having a different opinion of the other would only make different judgment and thus causes so much misunderstanding. Misunderstanding might cause danger into the couples bond.

I also think that a big reason couples break up is children. If they come into a relationship already having children, it is a huge problem sometimes.

not only bcs of money there is some more reason like ] 1. sexuality 2. likes 3. understanding not match 4. love with other or some more couple of reason there thats why couples break