Ramban, on Gen 29:30

“And having at length obtained the marriage he wished for, he preferred the love of the latter before the former, and served with him other seven years.”

“AND HE LOVED RACHEL MORE THAN LEAH. The reason why Scripture mentions that he also loved Rachel more than Leah is that it is natural for a man to have more love for the woman with whom he first had relations, just as the Sages have mentioned with reference to women: “And she makes a firm commitment only to he who marries her first.” Thus Jacob’s loving Rachel more than Leah was unnatural. This is the sense of the word gam: [and he loved ‘gam’ Rachel than Leah].”

Imported from an open dataset — not yet checked against the printed edition.