Pulsing through my veins
Our love was deep and pure
An aching heart and sadness
True love; the only cure

Good start

You had me from "Hello"
Like a whisper on the wind
I had a torn spirit
That you alone could mend

Good rhythm .going, uniform with the first stanza

Promises of a lifetime
Two hearts becoming one
Loving through it all
Our love a beacon like the sun

I love the poem until the last line of this stanza, the rhyme seems forced here.

But I've begun to falter
I'm not who I was
Life has begun to change
Just like it often does

Pressing into oblivion
Not knowing what's to come
A mistaken identity
Kills the love that was

Good rhythm, flow and rhyme aside from the one line I pointed out. Nice job!