Sforno on Genesis 29:30/ספורנו על בראשית כ״ט:ל׳

1ויאהב גם את רחל, not only because she was his wife, and such love is natural, but because she was Rachel, because of her distinct personality and her deeds which reflected this personality.

2מלאה, even though since she was his first wife it would have been natural for her to capture most of her husband’s love, (Yevamot 63) Yaakov preferred Rachel.