Why don't people understand why she'd be upset?
In their first scene together, their daughter is already sick, and Hugh and his wife talk about the lack of food in King's Landing and how desperate people have become.
In their next scene, she begs Hugh to leave the city and go to Tumbleton, where they can stay with her brother. Hugh refuses because he doesn't want to "turn beggar." His pride is what delays them leaving, and by the time he finally agrees, the city has been sealed and their daughter dies there.
When Rhaenyra calls for dragonseeds, Hugh's wife again begs him not to go. Instead of risking his life on what is essentially a suicide mission, she wants him to escape with her to Tumbleton. But Hugh chooses the chance at status and riches. She even tells him she doesn't care about becoming a Lady, she just wants her husband.
Believing Hugh is dead, she travels alone to Tumbleton, where she's assaulted on the road. When they finally reunite, she tells him her brother is dead, and Hugh's immediate response is to talk about becoming a dragonrider and how his position has been elevated. Then he asks her to leave with him while barely acknowledging the family she's about to abandon in a city on the brink of battle.
Throughout the story, Hugh repeatedly chooses pride and ambition over his wife and family. She has every right to be angry with him.