Relationships can bring out a range of emotions in people -- not just happy ones.
Jealousy, anger and guilt are emotions that often rise up between people when relationships turn sour.
In Paris With You:
The narrator is very bitter. he resents previous relationship: "I'm angry at the way I've been bamboozled"
He doesn't really seem to want to give this new relationship a chance: "Don't talk to me of love"
He is sunk in self-pity: "I get tearful"
It's almost as if he enjoys wallowing in his own self-pity.
The narrator is furious with her sister for telling her parents about her lover: "Who told my mother of my shame"
She sees her sister as a sneak: "Who lurked to spy and peer"
She wants her sister to suffer "Bide you with death and sin"
This is a dramatic monologue, so we only see the bitter view of the bitter sister.
The writer presents the younger brother as eager, innocent and childlike: "he skipped beside us"
The narrator was furious and impatient at being "saddled" by him.
He thought he knew it all, "doing what grown-ups do".
Looking back, he can see that he made a bad decision leaving the brother behind.
It seems to have caused a rift between them, : "the distance I'd set in motion", he blames himself.
Regret etc. cont.
The farmer's Bride:
He feels uncomfortable about his desire for his young bride whi has rejected him.
He is jealous of the animals : "I've hardly heard her speak at all"
His exclamation: "Oh! My god!" and the repitition of her features "the brown/The brown of her - her eyes, her hair, her hair!" suggests he is losing control.
Other poems can include negative emotions like: The Manhunt, Nettles, Harmonium, they show that even good relationships have an element of unhappiness.