They seem like they were in love. Didn't look like bad people. I guess made a mistake thinking she was the world. She was about to leave him and he lost his mind.
She probably found a better looking/higher status version of him and wanted to leave him so he lost it as he couldn't imagine living without her (true love). Remember females are hypergamous in nature and always looking for a better deal. She's not yours, it's just your turn.

"There’s a biological reason why a woman loves a man for what he can provide for her. Since the inception of our species we have had primal instincts that has shaped us. You can actually observe this in the animal kingdom.
The female is the one that sets up conditions for breeding and for this the female picks the “alpha” of the group so to speak. This here is the biological process where the female is hardwired to breed with the strongest, most fertile male with the most resources. The biggest bear, the fastest and most resourceful lion. They’re the ones who pass down their genes because the ones that are deemed unworthy either,
-Die out while fighting other males in order to claim the breeding spot.
-Gets no attention from the female as the male lacks the standards defined by the basic biological conditions of the female.
This entire process is called “Hypergamy” and is a female instinct put in place that ensures the safety of the female and it’s offspring. Those traits are indicative of a male of higher quality.
Now that we’re technologically advance (at least the west and the far east are) we can’t have those barbaric bloodbath to determine who gets to be the alpha breeder. Instead, wealth, social and political influence as well as physical features are associated with those alpha traits.
So,
*A good jawline, broader shoulders, bigger stature, more muscle mass as well as penis size indicates good genes which can be passed down through her.
*Wealth and financial stability ensures her safety and fulfillment in when it comes to having access to resources that can be put to her and her child’s benefit.
*Social influence, as in social reach such as celebrities, politicians, company shareholders or board members and so on ensures the male is in a dominant position in society where he is leading other men that are lower in the masculinity ladder which ensures female’s reach and influence by extension of being associated with said man.
Statistically (keeping all of these observations in mind) 80% of the females desire and attempt the top 20% of men because of again, what they are capable of. The rest of the 20% of females are simply not capable of that so they settle in for the bottom 40% of men or so. Now, those 80% of women don’t directly go for the millionaires and billionaires because of vast unreachability. So the process of, in layman’s term “monkey branching” occurs. It is, the act of getting together with man that isn’t too higher in range than her in order to use that man as a platform to search for even higher range men.
For example: You being an employee and your wife trying to hit on your boss or the other executives. Now, let this sink in because it’s gonna come full circle in a bit. This here is fueled by the female’s hypergamous hard-wiring to always search for a better deal, it is an unbeatable instinct that is tied to the female’s instinct to search more wealth, safety and influence for herself and her offspring.
Now, i told you to let something sink in right? Here’s how it’s coming back. Because of this very reason and process, 70–80% of all divorces are filed my women. 60% or so do it out of “i fell out of love with him” but what really happened is, she found a man that has everything her current man has, but multiple folds better. This kicks off the hypergamous “tingle” in their brain that mandates them to seek the best possible mate for herself and the offspring which evidently is the reason why women are having children in their late 30’s and early 40’s to even late 40’s because of waiting around to make sure she’s “not missing out on a better deal”."