"Before You Were Mine" is a free verse poem (not meter) with no end-rhymes that is structured in four stanzaic paragraphs. There is the repetition of the word "Before you were mine" in the second and fourth paragraphs:
... That glamorous love lasts
where you sparkle and waltz and laugh before you were mine.
The dominant theme is the poet's admiration and love for his mother and is inspired by an old photograph he'd seen of her showing her in her youth.
The poet is female, not male, as this answer implies.