Based on the classical earthly-branch relations of your two zodiac animals — this combination may emphasize these tendencies; real people add the nuance.
A natural six-harmony match
Horse and Goat sit in a classical six-harmony (Liu He) bond — the closest affinity two branches can have. Energy flows between them without effort: conversations click, silences feel comfortable, and each quietly covers the other's blind spots. In love this is the pairing matchmakers prized most; at work it shows up as seamless, almost telepathic collaboration.
Their difference in temperament is the point — each supplies exactly what the other lacks, so the partnership grows more resilient the longer it runs.