Veronica is not my favorite (Maggie, Alison and Little Jammin are ahead) but to be fair MC is not blameless in his whole situation. You could argue that the real flaw of Veronica is loving MC
MC/Jake doesn't consider her as his girlfriend, but in his presentation of the LI, the devs introduce her as Jake's girlfriend so the status of the relationship is ambiguous at the beginning. He has been with Veronica for 6 months so imo it's fair that Veronica wants to clarify their relationship. Feels like Jake is leading her on a bit. They fuck, she helps him with his research, he call her when him and Cooper are drunk and they need a ride but when she express interest in her life like meeting Cooper, meeting his daughter, Jake dodges it.
After Lily's accident, she is not even part of his support system, Maggie, Cooper and Alison fills that role. What's is even hilarious is that all she wants to do with Jake, Jake goes and does it with another LI first. She wants to really meet his best friend and getting to know him, Jasmine doing it, she wants to be there to support Jake after the accident, he opens up to Maggie. Hell even Maggie share breakfast with MC before poor Verinoca. He will try to win the money for her daughter with the races, she is not even aware, MC discuss it with Jasmine and depending of your choices, Allison.
She gets him invitations for the charity even, he doesn't even think to take her as his +1 before she propose herself (he always think about Natalya). She is his sidechick basically
That's why I think it is fair that she distance herself if MC choose to go with Jasmine. Jammin is mocking her and clearly flirt with MC and he goes along
Overall it is a strong point of this game, the LIs have their flaws just like MC