Netflix's Obsession ending explained: what happened to Jay, Anna and William in the series finale?

Netflix's new show Obsession is our most recent obsession and we can't get enough of *that* shocking ending.

The show depicts a respected London surgeon's affair with his son's fiancée as it turns into an erotic infatuation that threatens to change everyone's lives forever.

So if you're wondering does the Netflix show ending differ from the original book which Obsession is based on or what happened to the addictive main characters, here's the twist ending explained...

*Warning: spoilers ahead*

After four episodes of intense, well, obsession between William and his daughter-in-law/mistress, a happy ending for the pair was likely never on the cards. In the penultimate episode, the pair are caught by William’s son (and Anna’s fiancé) Jay.

A shocked Jay turns to leave, pursued by his naked father who abandons his tryst to try and stop him. But disaster strikes. William finds Jay in a pool of blood, after having fallen from the banister. Jay dies in his dad’s arms, never getting to really recover from the shock of finding his dad sleeping with his fiancée.

Losing his son isn’t the only karma William experiences. His wife Ingrid blames him for Jay's death and demands a divorce. Meanwhile, Anna decides to abandon it all and jets off on what would’ve been their honeymoon, alone. Proving that nothing can stop his obsession, William follows. He tracks a, seemingly unbothered Anna, down to a sunny spot where she could have been toasting her nuptials with Jay.

As they reflect on the chaos behind them, William tells Anna he "couldn't change a thing." But she decides to end it and tells him not to look for her again.

The next time we see them both, William appears to be alone, living in the flat that witnessed the death of both his son and his affair. He’s still obsessive, reading Anna’s diary.

Anna, meanwhile, is shown in therapy. But just as she begins to open up about her harrowing time with William, she shares a lingering look with her older therapist, reminiscent of the look that started it all with William.

Will the cycle continue for Anna? Netflix leaves that up to viewers’ imaginations, but it seems to hint that she will soon be starting another illicit affair with her therapist.

In the novel, Jay (called Martyn in the book) does tumble backward and falls down the stairwell to his demise. However, following the loss of his son, William's character (who's called Stephen and is a British politician instead of a surgeon) lives a solitary life abroad, consumed by his obsession. He spends his remaining days staring at photographs of Anna and his son which cover his walls.

Will there be an Obsession season 2?

The season ended with Anna sharing a sultry look with her therapist which led fans to hope this could be a signal of a second season and a new affair for the show to focus on.

However, Obsession has been billed as a standalone, limited mini-series made up of four hour-long episodes. Because of the source material, a second season is unlikely as Netflix does not have a sequel of the book to base the narrative on.