If we are talking about real love, a love soo powerful that even if you fight against it, over powering you and making you day dream about that special someone then it could happen since it happens in a molecular level deep in your mental chemistry. But the illusion of love could happen too and make you truly belive that you are in love with that someone when infact you are inlove with the idea of the version you created about that person. This happens usually when you have some unresolved issues with your current partner, resentment sinoreh or something like that your mind starts to be drawn to someone else by creating the idea of you finding what you have lost. Hope this helps🙏