This particularly individual is young, he's still undeveloped and maturing, he's naturally narcissistic and unempathic, it's all somewhat not surprising for a individual such as him to exist. This doesn't prevent him from learning from his mistakes, finding new relationships and correcting them. He does note that he was mostly at fault for the dissolution of the relationship, whether this was sincere or if he cares to change is up to him. In the gamut of humanity, he's just selfish, perhaps a bit callous and unempathic but he doesn't seem to be malignantly abusive since this sort of video got made.
Clashes are normal for relationships, and voicing concerns might be constructive for relations as well, this is often a way for people to develop. Something like duality doesn't mean absence of conflict. How relationship conflict resolves, and the tension and anxiety of conflict resolution will have much more to do with compatibility. A relationship that reduces anxiety even in conflict is something that would be healthy both psychologically and physiological , I think duality has the potential to offer such a relationship. But don't let you think this is boring, because boredom is in itself a form of anxiety, often relationships form from high anxiety, and devolve into boredom as this high tension experience overpowers the physiological system, which turns it into boredom. I think compatible relations avoid this high anxiety/boredom roller-coaster and stablize into more stable ups and downs. The nature and character of these up and downs can be very individual as well.
You can tell these two individuals did not really engage in very stable ups and downs, they were in a rocky relationship with likely a lot of tension and boredom, some of which might lead to cheating, reconciliation. This unstable pattern lasted a while but eventually it disintegrated. I have no problem characterizing this relation as some sort of benefit relation as this is rather common sort of relation that exhibit rocky patterns like this.