You think you are in love when what you feel for your partner makes you fulfilled. You will feel incomplete without the person in question. You will be restless when that person is not with you. Something must make you fall in love with that person, or make you behave in the aforementioned ways. You will be better prepared to adore your partner if you know why you think you are in love. Such knowledge will encourage you to assist them to preserve such qualities, so that you can remain in that mood.