True, Yaakov had feelings for Ruchel before they got married, but (as the mod nicely pointed out) that doesn’t mean that that must always be the case; feelings can and often do develop later on.
Of course, I’m not claiming that if you don’t fall in love before marriage, that you will certainly have a bad marriage. I’m just responding to those who claim that any love before marriage is necessarily fake and meaningless.
I fully believe that the level of love achieved after marriage cannot be achieved before marriage. But I think that the feelings that people do feel before marriage are real and valuable. And the absence of such feelings might ask a good question about your compatibility in a situation when you’ve been dating long enough that you’d expect such feelings to have developed.