While I personally think that Jacob was emotionally blackmailing Bella (telling her that he was going to let himself die so she would kiss him) and that led to the "realization of her feelings" and the kiss that followed, I do believe it's possible to love two people at the same time... it's happened to me before. You never love two people in exactly the same way and sometimes it just happens. In the case of Jacob/Bella, I don't think it was love as much as it was a force driving them together because of her daughter. I mean, as soon as Renesmee was born Jacob realized that it had always been her. "Loving" Bella, was just the universe trying to make sure that everything happened correctly. You can agree or disagree with me, but that is my opinion.