A theme of redemption could be there as well. Maybe the Spanish guy has a past mistake or a family curse that he is trying to overcome, and his love for the female character and his rides on the horse are part of his journey towards redemption. His horse could symbolize his freedom and his means to reach a better future with his love. Also, the theme of family could be intertwined. His family's expectations or his desire to start a new family with the woman he loves could be a driving force in the story, all while he is sitting on his trusty horse.
The theme of cultural identity might also play a role. As a Spanish character, his actions, values, and courtship style could be influenced by Spanish traditions. For example, his horse - riding skills could be part of his identity as a Spaniard, and this could be an attractive quality to the love interest in the novel. Additionally, the theme of the power of nature could be present. The horse represents a connection to nature, and his rides through the Spanish countryside could be a backdrop for his romantic encounters, with the beauty of nature enhancing the romantic mood.
Love and adventure would be a major theme. The Spanish guy on his horse could be off on a journey to find his true love or to protect the woman he loves. Another theme could be honor. In Spanish culture, honor is highly valued, and the character on the horse might be acting in a way that upholds his family's or his own honor while also being in love.