i think what i don't like about the ending of s3 is that it kind of romanticizes stalking, using the excuse of "true love".
First, Conrad writes her not one but multiple handwritten letters. Belly doesn't write back, doesn't give him any signs that this is okay, and yet he keeps sending her letters. He even admits in one of the letter that he doesn't know if she's reading them or even receiving them. I'm sorry, but that's kind of creepy. I feel like sending one letter and then waiting for her to respond - if she wans to - would have been more respectful and appropriate.
At that point, i think they haven't talked to each other since the wedding? (I might be wrong)
Also, something doesn't feel right about the letters. I feel like if Conrad had called her or texted her, she would have at least been able to see that it was him on the screen of her phone. The fact that one day Belly just gets her mail, like any other day, and there's a letter from him feels extra uncomfortable. Because of the surprise effect of it. Because you don't expect to receive handwritten letters all together, certainly not from your ex.
Then he sends her gifts on Christmas. Okay, fine, it's Christmas. Sure, why not. But he sends her Junior Mint with the freaking infinity necklace!! As Taylor says in the episode, that's loaded.
Like just imagine this in another context : your ex- who you haven't seen in months - is sending you a package with the necklage that symbolizes your past relationship and a stuffed animal he offered you when you were like 15. That's really weird to me.
And finally, he decides to show up in Paris, unannounced, uninvited, unwelcomed. This was the worst.
Remember : Belly hasn't asked for any of this. She's just trying to move on, to find herself, to live her life in Paris. And suddenly, here he comes !
Besides, he waits for her at her apartment. He doesn't call to say he's in Paris for a while and wants to catch up. He doesn't text and ask to meet her. He goes directly to her new address and corners her. It feels almost like a trap, like she's forced to confront him, like she can't avoid him, like she doesn't have a say in the matter.
In the end, she does choose Conrad (of her own free will) but up until that point, her consent isn't really taken into account. The show never really addressed that stalking your ex is not okay. Yes, even if you still love them. Yes, even if you think they feel the same. Yes, even if it's true love or destiny.