Romantic love suffers from its quid pro quo nature, and easily dies if constant effort is not maintained to keep the relationship vibrant. One of the greatest snarls of romantic love is the illusion of reciprocation. One's partner in romantic love is sometimes placed in higher esteem than one's self. Because of the quid pro quo nature of romantic love, we sometimes expect that if we give more and more to our partner, then we will receive more and more in reciprocation. This is not true.
Divine love is selfless love.
It is love regardless of gender, of race, of age. It is seen in familial and religious love, platonic love. Divine love has no physical representation. Divine love requires no response, no reciprocation. It has no limit.