There are a few. One of them is:
You´re still the one - Shania Twain
We were 15 and 18 when we met and I got pregnant

The lyrics to this song describe pretty well how I feel and how others thought our relationship would work out.
When I first saw you, I saw love.
And the first time you touched me, I felt love.
And after all this time, you're still the one I love.)
Looks like we made it
Look how far we've come my baby
We mighta took the long way
We knew we'd get there someday
Bridge:
They said, "I bet they'll never make it"
But just look at us holding on
We're still together still going strong
Chorus:
(You're still the one)
You're still the one I run to
The one that I belong to
You're the one I want for life
(You're still the one)
You're still the one that I love
The only one I dream of
You're still the one I kiss good night
Ain't nothin' better
We beat the odds together
I'm glad we didn't listen
Look at what we would be missin'
(Bridge)
(Chorus)
(Chorus)
I'm so glad we made it
Look how far we've come my baby
One of the other songs would be the Martina McBride song - There You are