it was a song in the 70's by a group called Siral Staircase here's something from a web site

Artist : Staircase Spiral Song : I Love You More Today Than Yesterday

I don't remember what day it was I didn't notice what time it was All I know is that I fell in love with you And if all my dreams come true I'll be spending time with you

Every day's a new day in love with you With each day comes a new way of loving you Every time I kiss your lips my mind starts to wander And if all my dreams come true I'll be spending time with you

Oh, I love you more today than yesterday But not as much as tomorrow I love you more today than yesterday But, darling, not as much as tomorrow

Tomorrow's date means springtime's just a day away Cupid, we don't need ya now, be on your way I thank the Lord for love like ours that grows ever stronger And I always will be true I know you feel the same way, too

Oh, I love you more today than yesterday But not as much as tomorrow I love you more today than yesterday But only half as much as tomorrow

Every day's a new day Every time I love ya Every way's a new way Every time I love ya Every day's a new day Every time I kiss ya Every day's a new day

sadly, now I can't get the sily tune out of my head!