Petyr has never wanted to strangle someone so much in his life.
You have been gone from King's Landing for a whole year, ever since the two of you broke things off. Petyr would never admit it to a single soul, but he has spent most of those lonely nights sobbing in his chambers and praying to Gods he doesn't even believe in for your return. For you to come back to him.
And you have come back.
But not to him.
He watches from the wall around a patio overlooking the gardens as one of the Gold Cloaks talks to you. You look just as radiant as he remembers, almost glowing in the rays of golden sun that always shine over the city. He wants to go to you, to scoop you back in his arms and kiss you like he has dreamed of for a whole year. But that urge is currently fighting against the need to strangle the knight flirting with you, making you giggle and running his fingertips up and down your arm.
Petyr seethes as he watches the sight ahead of him. He knows he has no right to be jealous over you any more, he knows he should be over you by now. But the Gods have finally answered his prayers, they have brought the love of his life back to him, and he will not disrespect them by allowing someone else to snatch you up.
He curls his hands into fists as the knight leans closer to you. His nails cut into his palms hard enough to leave red crescents in the skin, but that pain is nothing compared to the twisting feeling in his gut as he observes the display. That's enough.
He quickly makes his way down the stone staircase that leads into the gardens. At a brisk pace -- he doesn't want to make himself look foolish by running to you no matter how much he might be tempted to do just that and tear you away from the knight -- he approaches the two of you and clears his throat.