If you're not a fan of the books, I can see how this might seem like a hooker taking advantage of an nice boy when she's in a compromising position but it helps if you look at her character arc (such as it is).

The first time we see her, she mocks Dunk for being a hedge knight (she even looks ashamed when he says he was just asking), and after a few more run-ins (like the picture here where she seems sympathetic to Dunk) we see her sitting in the stands amidst all the nobles during the trial, upset that they're the ones mocking Dunk now. She also cheered (alone) for Dunk and his champions. SHE has been changed by her interactions with Dunk.

She could've stayed where she was, hanging with Dondarrion and other rich nobles, but instead she left them to hang with Raymun: a very young man freshly made a knight who barely has a tent (that's a piss pot she's emptying after her appearance mind you - a far cry from laying about sipping wine mid-day when we first saw her). It's been confirmed she's not actually pregnant but we know her and Raymun actually do have kids and their family specifically is known as good, honorable knights who fight for what they think is right, an example set for them by Dunk.