A tragic end to a young romance on Long Island has left a community in shock. A local teenager, whose identity remains undisclosed, took the life of his ex-girlfriend, Emily Finn, in a failed murder-suicide attempt, a situation described by a family friend as the result of a broken heart.

Emily, 18, had just begun her college journey, while her former boyfriend was preparing to enlist in the military. Faced with diverging paths, the couple decided to end their youthful relationship, according to the family friend, who spoke to The Post.

“It was a case of young, naive love that simply couldn’t last,” said the friend, who has known the alleged perpetrator since he was a child. “These teenage relationships often don’t endure, and this one was no different.”

Expressing bewilderment over the tragic turn of events, the friend added, “I can’t fathom what pushed him to such an extreme decision.”

Addressing public speculation, the friend firmly stated, “People online are suggesting she provoked him somehow, but that’s simply not true.”

Now, the teen is spending his 18th birthday and Thanksgiving in a hospital bed, recovering from a gunshot wound to the face and awaiting murder charges.

He allegedly gunned down Finn inside his Nesconset home around 11:10 a.m. on Wednesday, Suffolk County Police said.

Finn was reportedly returning some of the boy’s belongings to him following their recent breakup — a heartbreak he was not equipped to handle.

“The frontal lobe is still undeveloped and not equipped to handle and process these emotions. I went through breakups when I was younger and they’re awful but I never contemplated doing anything like this,” the friend said, adding that he was “disgusted” by the boy’s actions.

“That’s ultimately what this was. The inability of a young kid to process this. It feels like the world is coming to an end.”

The teen purportedly had shown no signs of violence leading up to the murder.

“His parents are very, very, very angry. It’s not a situation of, ‘My kid, my kid., No they’re holding him accountable,” the friend said, adding that they haven’t been inside the house since the tragedy: “They can’t come home. How would you be able to walk back into that house?” 

“Emily is dead. Her family is destroyed. These people lost their lives in an instant.” 

Finn’s grieving family declined to speak when approached by The Post Thursday, but an online fundraiser launched in the wake of her death described her as “a true treasure of a girl.”

“To know Emily is to love her, as she became part of the fabric of the lives she touched in her generous and kind way. Through her many years as a dancer, the children she taught as she prepared for a future as a teacher, and simply as a friend to so many, she will be sorely missed by all who knew her,” the fundraiser read.

Police have not yet publicly identified the alleged killer, but said he will be charged with second-degree murder and arraigned at a later date.

The full extent of his injuries was not clear, but authorities listed him in critical but stable condition.