The speaker looks back on a time of childlike happiness and a person who made everything feel safe. Back then, the speaker says, nothing frightening came near, and being with this person felt full of light. The memories are simple and warm: a smile, a laugh, a sense that nothing could go wrong.
Then the tone shifts. Time passes and the two drift apart, and the speaker hints that other people didn't understand how deep the feeling was ("what they didn't know"). The love never went away, and it hasn't now.
The poem ends on a quiet wish. If the other person came back, the speaker would simply say "I remember." The repeated word makes it feel like a promise of loyalty. The mood is tender and nostalgic, with a gentle ache underneath. The closing name, Donald, suggests the poem is addressed directly to him, which makes it feel like a personal message rather than a general reflection.