There are two type of happy romantic love poems in my opinion.
1. The “wedding vows” poem
2. The “renewal of vows” poem
Neither of these are strictly between spouses; the second option covers those who’ve been close for at least 10 years. I say 10 years, because if two people manage remain in love each other that long, they are more likely to always love each other. For the sake of comprehension, I’ll address only poems told through a first-person narrator, but these also apply to characters in a third-person narrator’s poems.
The “weddings vows” poems are about how much the poem’s narrator loves how his/her beloved is, why the narrator is in love with that person, and how their beloved affects them. These poems will fill the readers with warm fluffiness with their optimism for the future of the narrator’s and his/her beloved’s relationship.
The “renewal of vows” poems are about how the beloved of the poem’s narrator has inspired the narrator into a better person and how their loving relationship has changed the narrator’s life. These poems are raw and mature. These poems about real-life, and not fairy tale endings. Readers will have to think about these poems to appreciate them, because these poems will open the readers’ eyes. After 10+ years, lovers will have seen each other’s ugly side, because no one can maintain beauty and perfect all the time. Love is bittersweet, because no one is perfect, but together, two people can motivate each other to self-improve as much as possible.