Being in love is infatuation, it comes and goes like gas. When two people get married, they aren't vowing to always feel a certain way towards each other, but to act with love towards each other. Focusing on being in love before marriage is a problem because the infatuation blinds us to red flags, which can lead us to make poor decisions about whom to marry.
You should love a person and want to spend the rest of your life together before marriage, but not because of sex. That kind of love will blind you and inhibit you. But strong bonding is necessary and willingness to love after the feelings are somewhat gone. Being best friends is a helpful bond.
When deciding on one's life partner it should first be based on devoted friendship .... that of course should happen before marriage. Love as described by God is not an emotion ... but a principle (putting others before self) .... the emotional side of love is secondary ... and is enjoyed and experienced through an intimate relationship/expression with each other through marriage.
The person you are marrying should be your best and most trusted friend. Marriage is intended for a life time. Each must care about the other more than themselves.
If each lives by the 1st principle (putting the other before self) and are best friends .... the emotional side will be there as well.