I happen to went through a website talking about this.
Failing to keep promises, lying, or cheating. These blatant violations of trust often result in failed relationships. If the basic trust in a love relationship is repeatedly broken, the problems accumulate and the motivation to stay together decreases. Partners in healthy relationships agree to reconcile their differences – and if they keep their promises, the relationship can stay strong. However, consistent lying, cheating, or breaking of promises can explain why relationships end.
Ineffective communication. If both partners can’t share their thoughts, feelings, opinions, values, needs, frustrations, or even their joys, a failed relationship could result. If this was the cause of a breakup, then learning to love again could involve learning how to communicate effectively. This is a common reason for breaking up.
when things happens, we get to see the true colour of one another.
we always say it is pointless to compare whose fault is it, because i always believe everything take two hands to clap. But when things happen, each self will always start to push the blame to your partner even if you know it was your fault, each start to defend for themselves. I dont know if it is a normal thing, but for me i am, and i admit.
I posted this not because something happen to me, just that i happen to went through this and it just bring me to think about it.