Marriage is a lifetime relation.The base of marriage is love,trust & respect to each other.Though i would prefer to being honest but it actually depends on him whom u gonna married..he might not take the truth in a good way.But if he is intelligent enough then he might realise that you r fair with him...or if u not tell him whole life u ll feel guilty...
so,its up to u what u comforts u most.....
best of luck....