Simple things an encyclopedia can tell you

"There are two types of love in a relationship; passionate love and companionate love. With companionate love, potent feelings diminish but are enriched by warm feelings of attachment, an authentic and enduring bond, a sense of mutual commitment, the profound knowledge that you are caring for another person who is in turn caring for you, feeling proud of a mate's accomplishment, and the satisfaction that comes from sharing goals and perspective. In contrast, passionate love is marked by infatuation, intense preoccupation with the partner, strong sexual longing, throes of ecstasy, and feelings of exhilaration that come from being reunited with the partner."

(Hatfield, E., & Rapson, R. L. (1993). Historical and cross-cultural perspectives on passionate love and sexual desire. Annual Review of Sex Research, 4, 67-97)