If we ever need proof that sexism is still just a rife as ever, take a glance at reactions to this storyline. Peter kisses another woman on his wedding night and continues to cheat on his (pregnant) wife with her six months, lying to said mistress about loving her just to keep her sweet, and even planning, or pretending to plan, to run away with her, whilst also putting his wife through hell and basically living off her. And yet, when the truth comes out and Peter acts a bit upset, everyone immediately decides Carla is worth of no sympathy whatsoever because she's been less than saintly in the past, and forgives Peter because "he's always a cheat" and because he says he's sorry.
If Peter goes down for the murder then yeah, I'll feel bad for him for that because he genuinely didn't kill her. But beyond that, he deserves everything he's getting in my opinion.