help me understand lyrics

Once in a lifetime you'll open up your heart
Maybe once in your lifetime you'll swear to never be apart
You think your love's on solid ground
Then out of the blue, it all comes tumblin' down

Who's gonna hold me tonight, when I'm feeling lonely?
Who's gonna show me the light 'cause I need to know?
With all the things we've got, how can love just stop?
Tell me, somebody help me understand

And my picture in your locket, what will you do with it now?
All our friends and all our memories tell me how we sort them out
What's yours is yours, what's mine is mine
Is that all that's left after all this time?

Who's gonna hold me tonight, when I'm feeling lonely?
Who's gonna show me the light 'cause I need to know?
With all the things we've got, how can love just stop?
Tell me somebody help me understand

Why I'm not a part of your plan and you don't need me anymore
Help me understand why I still wanna be where you are
Even though I know in my heart that you don't love me anymore

Who's gonna hold me tonight, when I'm feeling lonely?
Who's gonna show me the light 'cause I need to know?
With all the things we've got, how can love just stop?
Tell me somebody help me understand