In order to fully understand Colin's reaction to the Lady Whistledown reveal and how he processes everything moving forward, you have to think about the entire season, the entire series really, through his point of view. I have no problems with the part 1/2 split. It made the anticipation that much more intense, and it worked out perfectly with their love story. But you can't separate one part from the other when you're thinking about his character.
In Colin's mind, the end of episode 4 is his happily ever after. That's it. He did it. He took action. He was the Cupid to her Psyche and played god and rescued her from a loveless match. He made shit happen and told her how he felt and they shared that moment in the carriage, and he gleefully proposed. He saved the girl and got the girl, and what a remarkable, enchanting, beautiful girl she is.
And aside from Eloise and Cressida, everyone's obsessed with their relationship. They're the true love match with a great story, and how lucky he is to fall in love with best friend. And she's showing hints of unease, but maybe that's just wedding jitters. Or maybe she's mourning her relationship with Eloise which is why he keeps trying to get them to make up. Or maybe she doesn't feel as secure with him as she would've with Debling, even though she'd never tell him that. He is the third son after all. And he still has no idea how in love with him she is.
So when she tells him how she's always loved him, he's warmed but also wracked with guilt. Because if he had only taken his stupid head out of his ass, he would've figured out why her letters meant so much to him or why he was eager to participate in an investment with her family or why her lack of response the past summer devastated him. He thought he was the instigator of their love. He's the one who laid himself bare and was like, is it possible you feel a fraction of what I feel for you? And to find out that she did always love him made him feel so undeserving. Because why would this exquisite siren still want anything to do with him after all that he put her through?
There is an incredible scene that I think deserves a lot more gravitas. The minute Penelope mourns Lady Whistledown and burns her issues, it cuts to Colin getting over his writer's block as he writes with great enthusiasm. It's like, he's unknowingly siphoning her power. He is Cupid and a writer and her protector and her provider and so madly in love. And he will finish his manuscript, and he will make things right with Penelope and Eloise. And he and Penelope will have the perfect life together.
And then everything he thought he knew about Penelope, about friendship, about love, is completely shattered. She rips his power from him, and he is absolutely gutted. She has been the mastermind this entire time, and he was none the wiser. And what part of their love story was even real? At which point was he manipulated into doing what she wanted him to do? And while he was helping her with her confidence, and telling her how changed of an individual he was, she not only saw through him but broadcasted his insecurities to the entire ton?
He's still so desperately in love that he remains steadfast in marrying her. But he cannot get over his fury and hurt and betrayal at that point. Which makes so much sense. It's painful to see him lash out and withdraw from her, but he's absolutely reeling.
And on top of all that, he is humiliated. He thinks about everything she said about his own writing. She told him how he made it seem effortless, which is such a great compliment. And he's like, I don't want you to edit my manuscript because I want to prove to you that I'm worthy of you. And he might be thinking, I can even give her some pointers for her own writing! What fun we'll have with more lessons. To find out that she's the talented, sharpest, most prolific writer in the ton fully emasculates him. He feels like she was patronizing him all along.
He brings that part up, and she's like, no, I meant everything I said about your writing. But he doesn't believe her and immediately switches the conversation to her dangerous predicament, so he can at least, at the very least, offer himself up as her protector. It worked before when he danced with Penelope after Cressida ruined her dress, when he rescued Marina from Rutledge, when he helped save Daphne's reputation, when he saved Penelope's family from Cousin Jack, when he helped save Will's business, when he kissed Penelope, when he saved her from the balloon, when he defended her to her mother... If he can't be the provider, he can be the protector. And she doesn't even want that from him. She's the knight in shining armor. She's Don Quixote. Not him. Never him.
So he is grappling with his role in their union. He figures it out, but it takes him a little bit to get there. And in the process, he not only remains in love with Penelope the entire time, but he also falls head over heels for Lady Whistledown.
