now i know why when we say i love you to one person, we don't use :
continous tense : because love is not just now and fade .
past tense : because love is not about the future, it's not a promise .
future tense : because love is about memory, it's about the past too .
we use present tense because when we say i love you, it's meant for forever, it's not just now, or just past, or it will happen in the future. love is about the past, now, and future. and also, i love you phrase is a fact, not a joke. we meant it, it's serious from the bottom of our heart. :]