How Will it Last?

Sometimes I feel as though
He doesn't want me
As much as I want him
He tells me he loves me so much
At that time I feel it too,
But other times I'm thinking;
We're so damn young
How's it gonna last with a male perspective
When the female feels this intensive love,
How is going to stay mutual?
Within the growing years
How will she age with grace
And he'll still notice her
And love her as if it was the first month
Of their romance
How well anything remain the same?
When all young lovers
Are now torn apart
She feeds upon love
Loathing any despair or anger
But here in the back of her mind
Are whispers of doubts and heartbreak
Because
"the saddest part of a broken heart,
isn't the ending so much as the start" Feist
So how can I be assured it'll last?
When everything I've ever felt or held
Has fell apart