Frank was Sam's and Annalise's guard dog long before Wes was Annalise's new favorite puppy.
He's not jealous, of course not. He deserves everything that happens to him. Greedy bitches get muzzled, and cute little puppies get loved, that's just how it goes.
(Frank has seen the way Annalise looks at Wes, desperate, like he's Damocles holding a sword above her head. Frank knows he looks at Sam that way when he thinks no one else is looking, and Sam knows how to take advantage of that.)
The puppy wants to become a lawyer after all, Frank supposes he knows how to play his cards right.
From one day to the other, there's suddenly an innocent slut's blood on his hands, and Frank hates that it's him who's the killer now, not Annalise or Sam or even Bonnie, that psychotic, jealous bitch.
It takes torturously long for Wes to end up with blood on his cute little paws without claws, too, but when he does eventually, the sudden shock of want that overcomes Frank as soon as he finds out about that nearly sweeps him of his feet.
"How'd you do it?," Wes asks, and Frank doesn't remember how he ended up in Annalise's basement, on his knees at Wes' feet, with the puppy staring down at him, looking more like a hungry wolf than anything else.
"With my hands," Frank breathes, and wants nothing more than for Wes to do the same for him.
In the end, Wes doesn't choke him to death only mere steps away from where Frank also didn't choke Rebecca to death, and he catches himself muttering What a pity under his breath.
(He supposes Wes heard him, because the next thing he knows, the wolf cub has backhanded him across the face so hard he tastes blood. Frank grins, bloodied, like a shark, waiting to be swallowed up my a megalodon.)
Eventually, Wes settles on something tamer - he might be a wolf, but only a cub, after all; he buys him a collar.