True love can never go away.
Human love is something else---a blend of the divine and the physical. I might imagine that couples are lucky if they would have known each other immediately past the passionate period. Passion usually dulls our sensibilities.
Depending on your perspective, you may choose to decide that love is a matter of commitment. You may choose to love the person for a lifetime, even beyond the time of physical attraction and romance.
Certain things may help you decide in making that commitment. What are you when you are with the person? Are you comfortable with yourself when the person is around or do you have to exert extra effort to put forth what you think is a "better" you. If you could be your natural self when you are around that person, he or she might be someone to keep for life, and making a commitment to love for.
So, yes, you can say that love is gone if what you're referring to is the passion or sexual attraction or the symbiotic stage of the relationship that usually lasts for about seven years. So theoretically, every relationship ends around that time if that is the basis of the relationship.
Otherwise, if your definition of love is a relationship of caring, in my opinion which changes as new experiences present themselves to me, it can last forever as long as there is a commitment to care for each other.