Remember, though: this wasn't really Pete's doing, other than Inoculating Sarah with Lycanthropy.
Sarah (per Wiki) decided to lose her Virginity to Peter, and Peter decided to help her. The only thoughts, either Sub- or Fully-Consious on Peter's part were "getting a piece"...of the action. (Gotta stay clean, here)
The reason that he made Sarah ( in both senses) was because he was deficient in the Werewolf "Birds and Bees" education to the point that he didn't connect having a good time with making a thrall.
That lack of knowledge, by the way, saved both their lives...
I have to wonder, though: back at the beginning of the Story, the Sheriff is telling Gus that the only reason he's alive is because it would be too hard to hide a Deputy's body... how would they have hidden Peter and Sarah's bodies?
I suspect that Peter is still not up to speed in the "Mated for Life"* bit, and neither is Sarah...after all, it's been less than forty-eight hours since Sarah first Wolfed out in the PiTW universe.
As for Choosing a Mate: I suspect Peter would have gravitated more to someone like Jean (not Jean herself) simply because he connects friendship and good times with a slender, sexy dark-haired female lilkle Jean Goodwin. Jean herself (per Wiki) has other aspirations for a significant other; and Peter isn't it. Still, I wonder what Becky has in mind for Peter...she's still after him.
As for nurturing and protecting Peter; why didn't Sally give him the facts of life when she saw her mate wasn't doing so...and why did she let Walt grind Peter's ego into nebbish-land? There's more here than meets the eye...or has been drawn. Only Kris knows for certain, and he ain't saying--so far.
*"Mated for Life" applies only within Peter's home pack's territory. I suspect that if he leaves that area, both he and Sarah will be free to choose. It'd be a hoot if, after all this, that they actually did come to care for each other...