Love as humans know it is not present in the lower intelligent species. Ours is more about Desire than survival. While mammals tend to experience an emotional attachment, the pairing is often developed for survival reasons; the ability to provide food, shelter, protection and survival of that species. This pairing is also driven by instinct not desire. Even those species who mate for life (Swan, eagle, wolves) will take a new mate at the next opportunity.
We tend to apply the attribute of love to our pets but this is more a form of dedication and affection than love. given the opportunity to hang with us or run after a female in heat, the unaltered male will bee line for the female in heat and return to us only after that issue is settled.
Additionally, "falling in love" and love are not the same thing. HOpe this answers your question.
They have no moral inhibitions and will have sex with whatever they can whenever they can. This is why dogs and cats are not given the ability to reproduce freely (neutering). The only animal that chooses and stays with just that animal for their entire life to my knowledge is a penguin.