The song is Chris Cagle's "What a Beautiful Day". I've linked to the CD in the sources section. The lyrics are as follows:
(verse 1)
Day 1 I stumbled through "Hello" on 5th Avenue
Day 2 We grabbed a bite to eat and talked all afternoon
We caught a movie on Day 14
And Day 67 she said "I love you" to me
(chorus)
Oh what a feeling
What a wonderful emotion
Yeah what a life
Counting my blessings and knowing
We had our up's and down's all along the way
She had a chance to leave but chose to stay
What a beautiful day
(verse 2)
What a beautiful day
Day 116 I asked her what she was doing for the rest of my life
Day 189 Oh I almost lost that girl to my foolish pride
She said "I do" on Day 482
And gave me a son on Day 761
(repeat chorus)
(tag 1)
Day 18,253
Well honey that's 50 years
Yeah here's to you and me
(repeat chorus)
(tag 2)
Day 1 I thank God I said "Hello" on 5th Avenue