My read on Kim's arc is that she is self-aware of how corrupting the power and wealth of her profession can be (corporate law, large firms like HHM, etc.) and she is actively sabotaging paths into that trap. Things like being a public defender at the local courthouse fit her desires more than being counsel for an expanding bank conglomerate. She's lived through the demeaning work and humiliation under Howard, and survived a car crash from being overworked on her own ventures. She was deeply affected by the unresolved rift between Chuck and Jimmy.
She genuinely cares for Jimmy, wants him to be a decent human being - suggestions for a therapist, seeing him get a legitimate job on the way to restoring his law license. I think his deceitful ways catch up to him and either have unintended consequences for Kim or otherwise ultimately drive them apart. Which is fascinating as it unfolds, seeing Jimmy continue to break bad and become Saul, as it costs him everything he once had (but yet he's an advocate for the common man and against the law establishment - just like Kim!).
